The Journal of molecular and cellular immunology : JMCI最新文献

{"title":"Regulation of Fc gamma 2a receptor-mediated phagocytosis by a murine macrophage-like cell line, P388D1: involvement of casein kinase II activity associated with Fc gamma 2a receptor.","authors":"A Yamada,&nbsp;K N Dileepan,&nbsp;D J Stechschulte,&nbsp;T Suzuki","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A question of whether or not casein kinase II (CKII) activity associated with Fc gamma 2aR is involved in the regulation of phagocytic process mediated by this type of Fc gamma R was investigated. Our previous studies showed that the rate of phagocytosis of sheep erythrocytes (SRBC) coated with anti-SRBC antibody (EA) by P388D1 cells varies significantly depending on the isotypes of antibody and that Fc gamma 2aR isolated from the detergent lysate of P388D1 cells is associated with CKII activity, whereas Fc gamma 2bR is not. Fc gamma Rs-mediated phagocytosis is a major function of macrophages by which invading pathogens such as bacteria could be eliminated and therefore warrants the investigation of its biochemical mechanisms. We have recently shown that phagocytosis of EA2b mediated by Fc gamma 2bR of P388D1 cells as well as murine peritoneal macrophages could be up-regulated by promoting the association of various cytoskeletal components with the receptor by inhibiting Fc gamma 2bR-associated phospholipase A2 (PLA2). CKII activity-associated Fc gamma 2aR mediates phagocytosis of EA2a more effectively than PLA2-associated Fc gamma 2bR mediates phagocytosis of EA2b. We have therefore examined a potential role of CKII in Fc gamma 2aR-mediated phagocytosis by the use of a specific inhibitor of CKII activity (heparin). Results showed that heparin inhibited CKII activity associated with Fc gamma 2aR and effectively down-regulated the Fc gamma 2aR-mediated phagocytosis by apparently blocking the association of the receptor with four types of cytoskeletal components (actin-binding protein, myosin heavy chain, alpha tubulin, and actin).(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 4","pages":"191-9; discussion 199-201"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13678131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unique V gene usage by B-Ly1 cell lines, and a discordance between isotype switch commitment and variable region hypermutation.","authors":"J Braun,&nbsp;L King","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We have previously described a series of Ly-1+ B cell lines obtained as spontaneous outgrowth cultures from mouse spleen cells (B-Ly1 cells). In this study, we report the variable region sequences utilized by independent cell lines derived from three mouse strains. Remarkably, V region utilization and junctional diversification were essentially identical in all three cell lines. These included: lambda 1 light chain; JH1; DSP2-7,8; and, a novel VH gene segement. The VH was highly homologous to CP4, a rare VH family previously found in a group of Ly-1 B cell-derived autoantibodies to bromelain-treated mouse red blood cells. The selective expression of this unusual lg species implies the action of distinctive molecular or immunophysiological processes in the outgrowth of B-Ly1 cell lines. Clarification of these factors may be relevant to understanding the peculiar biology of Ly-1 B cells in vivo. We have also evaluated switch-committed B-Ly1 clones to determine whether this phenotype is accompanied by variable region somatic mutation. However, no evidence for somatic mutation was observed in these induced clones. This may indicate that these two processes are independently regulated, despite their common concordance in vivo.</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 3","pages":"121-7; discussion 127-8"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13927451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Binding of radiation leukemia viruses to a thymic lymphoma involves some class I molecules on the T cell as well as the T cell receptor complex.","authors":"H C O'Neill","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Radiation leukemia virus (RadLV)-induced thymomas and malignant thymocytes from AKR mice have been shown to bind specifically retrovirus produced by these cell lines. Each lymphoma has been shown to have greatest specificity for cognate virus suggestive of an immune-specific receptor. The question of receptor identity has been addressed here using the RadLV-induced murine T cell lymphoma, C6VL/1, and antibodies specific for known cell surface determinants present on these cells. This lymphoma has been shown to bind both homologous and heterologous RadLV isolates, but to have greatest specificity for homologous retrovirus since homologous free virions can best block the interaction between cells and virus adhered to the wells of a microtitre plate. A clonotypic anti-TCR antibody has been shown to completely inhibit C6VL/1 binding to the homologous virus, RadLV/C6VL, but not to the heterologous virus, RadLV/VL3. Anti-CD4, anti-Thy1.2 as well as anti-H-2Kb and not anti-H-2Db antibodies were found to partially inhibit the interaction with both RadLV/C6VL and RadLV/VL3, yet neither of these virus preparations appears to be contaminated with Class I molecules as measured by radioimmunoassay. The binding interaction between C6VL/1 and RadLV/C6VL appears specifically to involve the TCR since antibody against the clonotypic site on the TCR heterodimer uniquely inhibits this interaction, while the binding of C6VL/1 to RadLV/VL3 appears to involve the H-2Kb molecule. When free virus particles were absorbed to receptors on C6VL/1, both RadLV/VL3 and RadLV/C6VL inhibited the binding of antibody to the TCR and CD4 molecules, while the binding of several anti-H-2Kb antibodies was specifically inhibited by RadLV/VL3. There are at least two known T cell surface structures involved in the interaction of the T cell lymphoma, C6VL/1, with RadLV. These are the TCR complex (comprising the TCR heterodimer and CD4), and the Class I H-2Kb molecule. Since the TCR molecule has been shown to comodulate with H-2Kb molecules when cells were cultured in the presence of anti-H-2Kb antibodies, and the CD4 and H-2Kb molecules have been shown to comodulate with the TCR on only a subpopulation of C6VL/1 cells treated with anti-TCR antibody, this suggests that the H-2Kb molecule may also be part of the larger molecular complex including CD4/8 which can form around the TCR heterodimer.(ABSTRACT TRUNCATED AT 400 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 4","pages":"213-23"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13701978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Direct activation of murine resting T cells by con A or anti-CD3 Ig.","authors":"J Quintáns,&nbsp;A Yokoyama,&nbsp;B Evavold,&nbsp;R Hirsch,&nbsp;R D Mayforth","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The induction of antigen-specific T cell activation is highly dependent on accessory cells (AC) which present processed antigenic fragments associated with MHC molecules and provide costimulatory signals for T cells. Antigen-specific T cell activation requires cross-linking of the TCR and the reception of one or more nonantigen-specific signals which eventually lead to T cell activation and proliferation. This sequence of events can be mimicked by lectins, bacterial enterotoxins, and anti-TCR antibodies in conjunction with APC or the combination of phorbol esters and Ca ionophores. Although the combination of PMA + Ca ionophore and certain types of T-T interactions result in APC independent T cell activation, it is generally assumed that physiologic T cell activation requires APC. The seemingly direct activation of T cells by other T cells is rather surprising in view of the known APC dependence of antigen, lectin and anti-TCR mediated T cell activation. It is conceivable that T cell mediated T cell activation is due to \"cryptic\" APC contamination because the total absence of APC is difficult to disprove. In reality, neither total depletion nor residual contamination with APC can be proven or disproven experimentally. Thus it can be legitimately argued that both APC dependent and independent T cell activation occur, albeit under different experimental conditions. For instance, it is possible that APC independent activation of T cells by lectins and anti-TCR antibodies would require high concentrations of activators to overide their dependence on APC. It is also conceivable and, in our opinion quite likely, that once activated, T cells could propagate T cell activation through T-T interactions. In this report we test two hypotheses: (1) The triggering of resting T cells leading to autocrine cell proliferation depends entirely on cross-linking TCR molecules, and (2) The presence of activated T cells facilitates TCR mediated activation of resting T cells without the participation of conventional APC. We present evidence that highly purified, small resting T cells can be reproducibly activated with high doses of ConA, plastic bound anti-CD3 mab and its F(ab')2 fragments. This APC independent response results in blastic transformation, expression of the IL2 Receptor, the secretion of IL2 and significant proliferation of both CD4+ and CD8+ murine T cells. These observations demonstrate that vigorous cross-linking of TCRs by anti-CD3 mab and, presumably ConA, is sufficient to induce T cell activation and autocrine (IL2 driven) proliferation.(ABSTRACT TRUNCATED AT 400 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 4","pages":"225-35; discussion 235-7"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13678132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymmetry in the recognition of antigen: self class II MHC and non-self class II MHC molecules by the same T-cell receptor.","authors":"P Portoles,&nbsp;J M Rojo,&nbsp;C A Janeway","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>One of the most puzzling observations in immunology is the very high frequency of T cells reactive to non-self MHC molecules. Earlier studies from our laboratory suggested that the same receptor on a cloned T-cell line recognized both self-class II MHC: antigen complexes and non-self class II MHC, the latter at a significantly lower affinity. This suggested that alloreactivity resulted from low affinity cross-reactions of the T-cell receptor to a ligand presented at high multiplicity. The present studies address the question of whether these two ligands are recognized symmetrically by this receptor, and of whether different subsites in the receptor recognize both classes of ligands equally. In the present studies, we have greatly extended our analysis of T-cell receptor recognition of antigen: self class II MHC and non-self class II MHC. Using Fab fragments of monoclonal anti-T-cell receptor antibodies as monovalent competitive antagonists of T-cell activation, the response of cloned H-2k T-cell line D10 to conalbumin: I-Ak and to the allogeneic ligands I-Ab,v,p,q was analyzed with monoclonal antibodies directed at 3 clonotypic epitopes and one on V beta. These studies confirmed our earlier finding that D10 activation by antigen: self class II MHC is more difficult to inhibit with clonotypic Fab fragments binding to three distinct clonotypic epitopes than are responses to non-self MHC. More importantly, the Fab fragment of anti-V beta monoclonal antibodies preferentially inhibit activation by antigen: self class II MHC, and do so more efficiently than expected, based on the numbers of molecules of Fab bound.(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 3","pages":"129-37"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13621953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The processing of antigen and anti-Ig by antigen-specific B cells.","authors":"C D Myers,&nbsp;E S Vitetta","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>B lymphocytes are very efficient antigen-presenting cells when they bear surface receptors for the antigen in question. However, there is very little known about the intracellular events occurring between the time B cells bind native antigen and present it in processed form to T cells. To analyze internalization and degradation of antigen versus anti-Ig or anti-MHC antibodies by B cells, we have used highly purified resting antigen-specific B lymphocytes that bind the hapten, trinitrophenyl. These cells were treated with [125I]-labeled trinitrophenylated antigens or with [125I]-labeled antibodies reactive with either cell surface immunoglobulin or major histocompatibility complex (MHC) (class I or class II) molecules. The fate of these proteins was followed by measuring the amount of acid soluble and insoluble radioactivity associated with the cells or released into the incubation medium. The cell-associated and released radioactivity was further analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Our results demonstrate that the kinetics of degradation of specific antigen into acid soluble fragments which are released into the culture medium closely parallel those with which B cells acquire the ability to specifically conjugate to carrier-specific T cells. In contrast, degradation of anti-Ig is more complete than the degradation of antigen but requires a longer period of time to reach completion. Furthermore, the initial release of soluble fragments of anti-Ig as compared to antigen into the culture medium is marginally slower. Finally, there is significant intracellular accumulation of degradation intermediates when anti-Ig is processed, but this is not the case with antigen.(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 4","pages":"179-87; discussion 187-90"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13752314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cognate interactions between helper T cells and B cells. I. Cloning and helper activity of a lymphokine-dependent helper T cell clone (Th-3).","authors":"R J Noelle,&nbsp;J McCann","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Two essential events in the development of humoral immune responses to thymus-dependent (TD) antigens are the physical interaction of helper T cells (Th) with B cells and the elaboration of Th-derived lymphokines. Understanding the respective contribution of Th-B cell contact vs. lymphokines in triggering B-cell growth and differentiation has been hindered by the capacity of most Th clones to provide both cell contact-dependent and lymphokine-dependent signals. Our approach to study the role of lymphokines in TD B-cell growth and differentiation was to select antigen-specific Th clones that were able to induce class II-restricted B-cell growth and differentiation only in the presence of exogenously added lymphokines. In such a way, selected Th clones would putatively be defective in lymphokine production, but able to provide cell contact-dependent signals. One clone selected in this manner, Th-3.1, has been instrumental in addressing the role of IL4 in TD B-cell responses. Upon co-culture of purified TNP-specific B cells (TNP-ABC), antigen, and Th-3.1, Th-3.1 was unable to induce TNP-ABC growth or differentiation unless an exogenous lymphokine source (EL4 SN) was provided. The reason for the exogenous lymphokine requirement was two-fold. First, it appeared that Th-3.1 required IL2 to produce lymphokines (IL4) essential for B-cell growth and differentiation. Second, even in the presence of antigen and IL2, the level of lymphokine production by Th-3.1 was insufficient to induce optimal B-cell responses. Because an exogenous source of lymphokines was essential for Th-3.1-induced TNP-ABC growth and differentiation, the requirement for specific lymphokines in TD B-cell responses could be addressed. One lymphokine shown to be necessary for Th-3.1-induced TNP-ABC growth and differentiation was IL4. Addition of anti-IL4 to culture or the depletion of IL4 from the exogenous lymphokine source reduced the TD proliferative and antibody response of TNP-ABC. Because the addition of IL4 alone was unable to restore helper activity, it was concluded that IL4 was necessary but not sufficient for TD B-cell growth and differentiation. Pre-incubation of TNP-ABC and IL4 overcame the IL4 requirement when co-cultured with Th-3.1 and antigen.(ABSTRACT TRUNCATED AT 400 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 3","pages":"161-73; discussion 173-5"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13671719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expression and regulation of interleukin-1 mRNA and interleukin-1 receptors in human B-cell lines.","authors":"J Bertoglio,&nbsp;J Dosda,&nbsp;R Stancou,&nbsp;E Wollman,&nbsp;D Fradelizi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Long-term human lymphoid B-cell lines have been described to produce a number of growth factors, including interleukin-1 (IL-1) which may be of importance in the autocrine growth regulation of these cells and may participate in their antigen presenting function. In this report, we have analyzed the production of IL-1 by 12 established B-cell lines at the level of mRNA expression. Among the 5 cell lines containing an IL-1 message, three expressed exclusively IL-1 alpha, one contained traces of IL-1 beta, and only one line contained both. The steady-state level of IL-1 alpha mRNA in these cells could be drastically increased by a short culture of the cells with the protein synthesis inhibitor cycloheximide or with PMA. PMA, however, induced a transient increase in mRNA which could be stabilized by Ca2+ ionophore. Furthermore, only constitutively produced IL-1 mRNA are increased by these compounds which do not induce de novo transcription of silent IL-1 genes in these lines. These data provide the basis for further investigations on the regulation of IL-1 mRNA expression in human B cells. In addition, we studied expression of IL-1 receptors in these lines and observed that only cells which produce IL-1, displayed IL-1 receptors at their surface, as detected by radiolabeled IL-1 binding experiments. These data strongly suggest an autocrine role for IL-1 in these lines. IL-1 mRNA and IL-1 receptors were reciprocally regulated by PMA, which increased IL-1 mRNA and lowered the number of receptors.(ABSTRACT TRUNCATED AT 250 WORDS)</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 3","pages":"139-47; discussion 148"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13671718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interleukin 6 is the principal cytolytic T lymphocyte differentiation factor for thymocytes in human leukocyte conditioned medium.","authors":"J E Ming,&nbsp;C Cernetti,&nbsp;R M Steinman,&nbsp;A Granelli-Piperno","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The formation of CD8+ killer cells from nonlytic thymocyte precursors is mediated by interleukin 2 and a cytokine termed CTL differentiation factor (CDF). While several reports have focused on the effects of recombinant molecules on the development of CTL, the natural protein responsible for CTL development that is produced by normal leukocytes has not been conclusively identified. A 24 kD native protein with CDF activity was enriched from leukocyte conditioned medium and neutralizing antibodies were produced. Utilizing immunoaffinity chromatography and reverse phase chromatography, we purified this CDF to homogeneity. All 21 amino acid residues at the NH2-terminus of CDF were found to be identical to that of IL-6. Natural CDF and IL-6 share many of the same biological properties, including costimulation of thymocyte proliferation with IL-1. Antibodies against CDF or IL-6 can block the activity of either cytokine, and anti-CDF blocks the activity of bulk leukocyte conditioned medium. These results indicate that IL-6 is the principal CTL differentiation factor produced by stimulated human leukocytes.</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"4 4","pages":"203-11; discussion 211-2"},"PeriodicalIF":0.0,"publicationDate":"1989-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13752315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrastructural study of internalization and recycling of antigen by antigen presenting cells.","authors":"J Lin,&nbsp;J A Berzofsky,&nbsp;T L Delovitch","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The evidence which suggests that a helper T (Th) cell recognizes a processed form of a soluble protein antigen in association with a class II MHC antigen on the surface of an antigen presenting cell (APC) has raised many questions and much controversy. A major question that remains unanswered is what is the cellular site(s) and mechanism(s) in which such an antigen is handled by an APC. The controversy relates to the issue of whether a protein antigen is required to be processed by an APC before it is presented to a Th cell. A currently favored hypothesis of antigen presentation, which stems mainly from analyses of T cell reactivity to peptides of protein antigens, is that such antigens are internalized by an APC, processed intracellularly, recycled to the cell surface and then presented to Th cells. As a first test of this hypothesis, we reasoned that although it is currently difficult to study the biochemistry of antigen processing, it is possible to study whether a protein antigen is internalized by an APC and recycled to its surface. In this report, colloidal gold conjugates of pork insulin (PI-Au), a tryptic peptide of pork insulin lacking the insulin receptor-binding portion of the molecule (TI-Au), myoglobin (MYO-Au), and apomyoglobin (APO-Au) were used to follow the pathway(s) and kinetics of antigen internalization and recycling in TA3 B hybridoma cells. Transmission electron micrographs of the routes followed by the PI-Au and TI-Au conjugates suggest that these antigens are internalized and recycled to the surface of an antigen presenting cell within 2-4 hr. In contrast, the patterns obtained for MYO-Au and APO-Au suggest that either the internalization of these antigens serves to channel them into a degradative pathway or that the kinetics of recycling of these antigens is slower. The two types of patterns observed may not be mutually exclusive and the purpose of internalization may vary, depending on the nature of the antigen. These data represent the first analysis of the kinetics and pathways of internalization and recycling of an antigen by an APC. It is impossible to formally prove that the pathway we have demonstrated is the one responsible for processing for antigen presentation. Nevertheless, these results support the notion that a protein antigen is handled intracellularly by an APC and recycled to the surface before it is presented to a Th cell.</p>","PeriodicalId":77639,"journal":{"name":"The Journal of molecular and cellular immunology : JMCI","volume":"3 6","pages":"321-45"},"PeriodicalIF":0.0,"publicationDate":"1988-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14207428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}