Effects of Plasmodium berghei infection on the expression of salivary gland immune-related genes in the Anopheles stephensi mosquito.

Background: Achieving malaria eradication by 2050 will require the development of novel transmission-blocking strategies alongside existing and emerging control measures. Since the innate immune responses of Anopheles salivary glands determine its vectorial capacity, a detailed assessment of vector-parasite interactions could help identify novel targets that play key roles in the immune response against Plasmodium. In this study, six candidate immune-related genes from Anopheles stephensi salivary gland transcriptomic datasets were selected, and their expression changes were assessed following Plasmodium berghei infection.

Methods: Using RT-qPCR, gene expression profiles at 18 days (early phase) and 21 days (late phase) post-infection were analysed, and the results were compared with those of uninfected mosquitoes.

Results: A significant upregulation of LRIM8A and DEF1 gene expression was observed at both time points, whereas TEP-12 expression was significantly increased only at day 21. However, no significant changes were observed for P37NB, CLIPA4, and CLIPC4. Among the highly expressed genes, LRIM8A exhibited the highest expression during both the early and later phases of salivary gland infection.

Conclusions: The highest expression levels of LRIM8A at both early and late phases of salivary gland infection underscore its potential as a key immune effector. However, further functional assays are required to validate the role of LRIM8A in mosquito innate immunity. A deeper understanding of the immune mechanisms in Anopheles following Plasmodium infection could contribute to the development of novel malaria control strategies.