Endogenous CD4+ CD25+ regulatory T cells play no apparent role in the acute humoral response to intact Streptococcus pneumoniae.
Immunoglobulin G (IgG) antiprotein and antipolysaccharide responses to intact Streptococcus pneumoniae are CD4+-T-cell dependent and therefore might be under the negative control of CD4+ CD25+ regulatory T cells. Injection of anti-interleukin 2 receptor alpha (anti-IL-2Ralpha) MAb to deplete regulatory T cells, injection of agonistic MAb against glucocorticoid-induced tumor necrosis factor receptor family-related protein to inhibit regulatory-T-cell function, and adoptive transfer of regulatory-T-cell-depleted CD4+ T cells into athymic nude mice each had no effect on either the primary or secondary protein- or polysaccharide-specific IgG response to intact S. pneumoniae. Surprisingly, anti-IL-2Ralpha MAb also had no effect on the IgG response to intact S. pneumoniae in MyD88-/- mice or to a soluble protein-polysaccharide conjugate injected into wild-type mice in the absence of adjuvant. Collectively, these data are the first to suggest that, in contrast to their role in limiting chronic cell-mediated immunity, regulatory T cells may play no significant role in an acute humoral immune response to an intact extracellular bacterial pathogen.
Department of Pathology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, USA.
Katherine S
KS
Lee
Goutam
G
Sen
Clifford M
CM
Snapper
D048868:Adaptor Proteins, Signal Transducing; D019264:Adoptive Transfer; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000943:Antigens, Differentiation / Q000502:physiology; D001426:Bacterial Proteins / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D005260:Female; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification; D051379:Mice; D008807:Mice, Inbred BALB C; D053594:Myeloid Differentiation Factor 88; D011971:Receptors, Immunologic / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D013296:Streptococcus pneumoniae / Q000276:immunology*
D048868:Adaptor Proteins, Signal Transducing; D000907:Antibodies, Bacterial; D000943:Antigens, Differentiation; D001426:Bacterial Proteins; D007074:Immunoglobulin G; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; C051592:pneumococcal surface protein A