Gamma delta T cell help of B cells is induced by repeated parasitic infection, in the absence of other T cells.
BACKGROUND
gamma delta T cells, like alpha beta T cells, are components of all well-studied vertebrate immune systems. Yet, the contribution of gamma delta T cells to immune responses is poorly characterized. In particular, it has not been resolved whether gamma delta cells, independent of any other T cells, can help B cells produce immunoglobulin and form germinal centers, anatomical foci of specialized T cell-B cell collaboration.


RESULTS
TCR beta-/- mice, which lack all T cells except gamma delta T cells, routinely displayed higher levels of antibody than fully T cell-deficient mice. Repeated parasitic infection of TCR beta-/- mice, but not of T cell-deficient mice, increased antibody levels and induced germinal centers that contained B cells and monoclonal gamma delta cells in close juxtaposition. However, antibody specificities were more commonly against self than against the challenging pathogen. gamma delta T cell-B cell help was not induced by repeated inoculation of TCR beta-/- mice with mycobacterial antigens.


CONCLUSIONS
In the absence of any other T cells, gamma delta T cell-B cell collaboration can be significantly enhanced by repeated infection. However, the lack of obvious enrichment for antibodies against the challenging pathogen distinguishes gamma delta T cell help from alpha beta T cell help induced under analogous circumstances. The increased production of generalized antibodies may be particularly relevant to the development of autoimmunity, which commonly occurs in patients suffering from alpha beta T cell deficiencies, such as AIDS.
Pao
W
W
Department of Biology, Yale University, New Haven, Connecticut 06520, USA.
Wen
L
L
Smith
A L
AL
Gulbranson-Judge
A
A
Zheng
B
B
Kelsoe
G
G
MacLennan
I C
IC
Owen
M J
MJ
Hayday
A C
AC
D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood*; D000913:Antibodies, Protozoan / Q000097:blood*; D001402:B-Lymphocytes / Q000276:immunology*; D015704:CD4 Antigens / Q000032:analysis; D003048:Coccidiosis / Q000276:immunology; D004539:Eimeria / Q000276:immunology; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D018858:Germinal Center / Q000276:immunology; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008817:Mice, Mutant Strains; D016692:Receptors, Antigen, T-Cell, gamma-delta; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000974:Antibodies, Antinuclear; D000913:Antibodies, Protozoan; D015704:CD4 Antigens; D007074:Immunoglobulin G; D016692:Receptors, Antigen, T-Cell, gamma-delta