Germinal center B cell depletion diminishes CD4+ follicular T helper cells in autoimmune mice

• Published in: PloS one 2014-08, Vol.9 (8), p.e102791-e102791
• Main Authors: Yusuf, Isharat, Stern, Jessica, McCaughtry, Tom M, Gallagher, Sandra, Sun, Hong, Gao, Changshou, Tedder, Thomas, Carlesso, Gianluca, Carter, Laura, Herbst, Ronald, Wang, Yue
• Format: Article
• Language: English
• Subjects: Animal models; Animals; Antigens; Arthritis; Autoimmune diseases; Autoimmune Diseases - immunology; B-Lymphocytes - cytology; B-Lymphocytes - immunology; B-Lymphocytes - physiology; Biology and Life Sciences; CD28 antigen; CD4 antigen; Cell adhesion & migration; Cell Differentiation - immunology; Cell growth; Cytokines; Dendritic cells; Depletion; Germinal Center - cytology; Germinal Center - immunology; Germinal Center - physiology; Germinal centers; Helper cells; Immunization; Immunological memory; Immunotherapy; Inflammation; Laboratory animals; Lupus; Lymphocyte receptors; Lymphocytes; Lymphocytes B; Maintenance; Memory cells; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred NZB; Models, Immunological; Plasma cells; Proteins; Rodents; Signal Transduction; T cell receptors; T-Lymphocytes, Helper-Inducer - cytology; T-Lymphocytes, Helper-Inducer - immunology; T-Lymphocytes, Helper-Inducer - physiology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0102791

Continuous support from follicular CD4(+) T helper (Tfh) cells drives germinal center (GC) responses, which last for several weeks to produce high affinity memory B cells and plasma cells. In autoimmune Sle1 and NZB/W F1 mice, elevated numbers of Tfh cells persist, promoting the expansion of self-reactive B cells. Expansion of circulating Tfh like cells have also been described in several autoimmune diseases. Although, the signals required for Tfh differentiation have now been well described, the mechanisms that sustain the maintenance of fully differentiated Tfh are less understood. Recent data demonstrate a role for GC B cells for Tfh maintenance after protein immunization. Given the pathogenic role Tfh play in autoimmune disease, we explored whether B cells are required for maintenance of autoreactive Tfh. Our data suggest that the number of mature autoreactive Tfh cells is controlled by GC B cells. Depletion of B cells in Sle1 autoimmune mice leads to a dramatic reduction in Tfh cells. In NZB/W F1 autoimmune mice, similar to the SRBC immunization model, GC B cells support the maintenance of mature Tfh, which is dependent mainly on ICOS. The CD28-associated pathway is dispensable for Tfh maintenance in SRBC immunized mice, but is required in the spontaneous NZB/W F1 model. These data suggest that mature Tfh cells require signals from GC B cells to sustain their optimal numbers and function in both autoimmune and immunization models. Thus, immunotherapies targeting B cells in autoimmune disease may affect pathogenic Tfh cells.