Evaluation of CD4+/CD8+ T-cell expression and IFN-γ, perforin secretion for B–T constructs of F1 and V antigens of Yersinia pestis

• DOI: 10.1016/j.intimp.2011.10.012
• Publication Date: 2011-11-18T05:45:32Z
• Authors: Geetanjali Gupta; Riyasat Ali; Arif Azam Khan; D.N. Rao
• Keywords: CD4-Positive T-Lymphocytes; Pore Forming Cytotoxic Proteins; Antigens, Bacterial; Mice, Inbred BALB C; Plague; 0303 health sciences; Perforin; Yersinia pestis; Vaccination; Epitopes, T-Lymphocyte; CD8-Positive T-Lymphocytes; 3. Good health; Interferon-gamma; Mice; 03 medical and health sciences; Bacterial Proteins; Animals; Epitopes, B-Lymphocyte; Female; Interleukin-4; Peptides

Yersinia pestis is a facultative bacterium that can survive and proliferate inside host macrophages and cause bubonic, pneumonic and systemic infection. Understanding the immune response generated by epitopes recognized by CD4+ and CD8+ T cells is important for the development of safe and effective vaccines designed to promote protective cellular immunity. Apart from humoral response, CD4+ T cells have shown to have a major role in combating the pneumonic form of the disease. In the present study, the secretion of IFN-γ and IL-4 by splenocytes, stimulated by different constructs of B and T cell epitopes of F1 and V antigens, was measured by ELISpot assay. We also measured perforin and IFN-γ expression as a function of cell mediated immunity by flow cytometry. Three B-T constructs of F1 and seven B-T constructs of V antigens produced a high number of IFN-γ secreting cells as compared to native antigen and a low number of IL-4 secreting cells. B-T conjugates of F1 and V antigens showed significantly high (p<0.001) percentage of CD4+ IFN-γ(+) cells as compared to CD8+ IFN-γ(+) cells. Thus, the study highlights the importance of Th1 cytokine and existence of high proportion of CD4+ T cells probably contributing protection in the host. This study proposes a new perspective for the development of vaccination strategies for Y. pestis that trigger T cell immune response.