Human follicular helper T lymphocytes critical players in antibody responses

• Autor(a) principal: Alonso,Giovana Toledo
• Data de Publicação: 2021
• Outros Autores: Fomin,Denilson Stork, Rizzo,Luiz Vicente
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Einstein (São Paulo)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-45082021000100600
• topic: Follicular CD4 T cells; Germinal center; B-lymphocytes; T-lymphocytes; Antibodies

ABSTRACT Follicular helper T lymphocytes are a subpopulation of CD4+ T lymphocytes initially identified in germinal centers of follicles found in secondary lymphoid organs. The primary function of follicular helper T lymphocytes is to help B lymphocytes’ antibody production. Changing of antibody class and affinity, B cell differentiation and memory generation depend on cooperation between follicular helper T lymphocytes and B cells. In blood, follicular helper T lymphocytes are called circulating follicular helper T lymphocytes. They are considered to have specificities similar to those developed in the secondary lymphoid organs. The phenotype of human follicular helper T lymphocytes is given by simultaneous expression of the markers CXCR5, Bcl-6, CD40L, PD-1, and ICOS. In germinal centers, follicular helper T lymphocytes synthesize interleukin 21 as predominant cytokine. In blood, subpopulations of circulating follicular helper T lymphocytes can be recognized, with different expressions of the classical follicular helper T lymphocytes markers and, in addition, can express other markers such as CXCR3 and CCR6. Presently, there is great interest in follicular helper T lymphocytes and circulating follicular helper T lymphocytes in vaccination studies as indicators of immunization efficacy. In addition, follicular helper T lymphocytes are investigated as possible markers of activity in many diseases and potential therapeutic intervention. This short review describes aspects of immunobiology and quantification of follicular helper T lymphocytes and circulating follicular helper T lymphocytes, and presents a few examples of related findings in systemic lupus erythematosus, rheumatoid arthritis, HIV infection and vaccination.