Suppression of cytokine production by supernatants from CD8+ lymphocytes activated by mycobacterial fractions: the role of interleukins 4 and 6.
Supernatants derived from CD8+ lymphocytes treated with mycobacterial components, or the partially purified carbohydrates from these supernatants, increased the production of IL-4 and IL-6 by mononuclear cells. The addition of anti-IL4 or anti-IL6 antibodies to LPS stimulated MN cells incubated with supernatants from CD8+ lymphocytes or carbohydrates resulted in the restoration of other cytokine production by these MN cells. Recombinant IL-4 and IL-6 on their own suppressed the production of IL-1 beta, TNF-alpha, IL-2 and IFN-gamma by mononuclear cells. Such suppression could be reversed with antibodies to IL-4 and IL-6. The addition of rIL-4 and rIL-6 did not increase the suppression of cytokine production induced by suppressor supernatants or carbohydrates. Interleukin 4 decreased the production of IL-6 by MN cells; whilst IL-6 suppressed IL-4 production in a dose dependent manner. Both effects could be reversed with the appropriate antisera. Our results suggest that mycobacteria could evade host immunity by inducing the production of IL-4 and IL-6 by host mononuclear cells. These cytokines, in turn, would suppress the production of other cytokines necessary for effective cellular immunity.
Wadee
A A
AA
Department of Immunology, School of Pathology of the University of the Witwatersrand, Johannesburg, RSA.
Sussman
G
G
Kuschke
R H
RH
Reddy
S G
SG
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002241:Carbohydrates / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D015847:Interleukin-4 / Q000096:biosynthesis / Q000494:pharmacology*; D015850:Interleukin-6 / Q000096:biosynthesis / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D009161:Mycobacterium / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013491:Suppressor Factors, Immunologic / Q000502:physiology*
D002241:Carbohydrates; D016207:Cytokines; D015850:Interleukin-6; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D013491:Suppressor Factors, Immunologic; D015847:Interleukin-4