[HTML][HTML] Loss of circulating CD4 T cells with B cell helper function during chronic HIV infection

KL Boswell, R Paris, E Boritz, D Ambrozak… - PLoS …, 2014 - journals.plos.org
KL Boswell, R Paris, E Boritz, D Ambrozak, T Yamamoto, S Darko, K Wloka, A Wheatley
PLoS pathogens, 2014journals.plos.org
The interaction between follicular T helper cells (TFH) and B cells in the lymph nodes and
spleen has a major impact on the development of antigen-specific B cell responses during
infection or vaccination. Recent studies described a functional equivalent of these cells
among circulating CD4 T cells, referred to as peripheral TFH cells. Here, we characterize the
phenotype and in vitro B cell helper activity of peripheral TFH populations, as well as the
effect of HIV infection on these populations. In co-culture experiments we confirmed …
The interaction between follicular T helper cells (TFH) and B cells in the lymph nodes and spleen has a major impact on the development of antigen-specific B cell responses during infection or vaccination. Recent studies described a functional equivalent of these cells among circulating CD4 T cells, referred to as peripheral TFH cells. Here, we characterize the phenotype and in vitro B cell helper activity of peripheral TFH populations, as well as the effect of HIV infection on these populations. In co-culture experiments we confirmed CXCR5+ cells from HIV-uninfected donors provide help to B cells and more specifically, we identified a CCR7highCXCR5highCCR6highPD-1high CD4 T cell population that secretes IL-21 and enhances isotype-switched immunoglobulin production. This population is significantly decreased in treatment-naïve, HIV-infected individuals and can be recovered after anti-retroviral therapy. We found impaired immunoglobulin production in co-cultures from HIV-infected individuals and found no correlation between the frequency of peripheral TFH cells and memory B cells, or with neutralization activity in untreated HIV infection in our cohort. Furthermore, we found that within the peripheral TFH population, the expression level of TFH-associated genes more closely resembles a memory, non-TFH population, as opposed to a TFH population. Overall, our data identify a heterogeneous population of circulating CD4 T cells that provides in vitro help to B cells, and challenges the origin of these cells as memory TFH cells.
PLOS