Cutting edge: CD4 is not required for the functional activity of IL-16.
IL-16 functions as a chemoattractant factor, inhibitor of HIV replication, and inducer of proinflammatory cytokine production. Previous studies have suggested that CD4 is the receptor for IL-16, because only CD4+ cells respond to IL-16 and both the anti-CD4 Ab OKT4 and soluble CD4 can block IL-16 function. However, these are only indirect evidence of a requirement for CD4, and to date a direct interaction between IL-16 and CD4 has not been shown. In this paper, we report that cells from CD4 knockout mice are as responsive to IL-16 as their CD4 wild-type equivalents in both assays testing for IL-16 function (chemotaxis and production of proinflammatory cytokines). In addition, the inhibitory effect of soluble CD4 on IL-16 function observed using CD4 wild type murine cells was not observed using CD4 knockout cells. These data demonstrate that CD4 is not required for IL-16 function and suggest that another molecule acts as the major receptor.
Mathy
N L
NL
Paul-Ehrlich Institute, Langen, Germany. matna@pei.de
Bannert
N
N
Norley
S G
SG
Kurth
R
R
D000818:Animals; D015704:CD4 Antigens / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D016207:Cytokines / Q000378:metabolism*; D007375:Interleukin-1 / Q000378:metabolism; D019410:Interleukin-16 / Q000502:physiology*; D015850:Interleukin-6 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015704:CD4 Antigens; D016207:Cytokines; D007375:Interleukin-1; D019410:Interleukin-16; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha