Hapten-specific unresponsiveness in mice. IV.--Significance of anti-hapten antibody responses elicited by E. coli lipopolysaccharides in tolerant mice.

The antibody response to lipopolysaccharide (LPS) and trinitrophenol-LPS (TNP-LPS) was investigated in mice after tolerance induction to chemically reactive hapten 2-4-6-trinitrobenzene sulphonic acid. The depression of the anti-TNP IgM response elicided by LPS was moderate and lasted 1 week. Depression of the response to TNP-LPS was severe and lasted 5 weeks. Tolerant mice given LPS 7 days after tolerance induction, at a time when it elicited a normal response, and challenged with TNP-LPS 2 weeks later, exhibited the same depression of their anti-TNP response as tolerant mice not given LPS. Furthermore, the anti-TNP IgM elicided by TNP-LPS in normal mice was of higher avidity than that observed with LPS. These results suggest that the anti-TNP response elicided by LPS cannot account for the overall immune status of tolerant mice.