Suppression of immune responses to sheep erythrocytes by the lymphokine soluble immune response suppressor (SIRS) in vivo.

Abstract

Soluble immune response suppressor (SIRS) is a protein produced by activated suppressor T lymphocytes which inhibits division by tumor cells and plaque-forming cell (PFC) responses in vitro. Although this lymphokine has been fairly well characterized in vitro, little is known about its effects in vivo. Purified murine SIRS, 10(3) to 10(4) U injected i.p., suppressed murine PFC responses to sheep erythrocytes (SRBC) in vivo. Suppression occurred when SIRS was injected into mice 5 days before assay, and also occurred when SIRS activated with 10(-6) M H2O2 was injected 24 hr before assay. These kinetics are similar to those observed in tissue culture, where suppression of PFC responses requires the addition of SIRS 4 to 5 days before assay unless SIRS is activated to SIRSox by H2O2. Levamisole, an inhibitor of SIRS-mediated suppression in vitro, also blocked suppression by SIRS in vivo. Delayed-type hypersensitivity reaction to footpad injection of SRBC was also inhibited by SIRS. Suppression of PFC responses by recombinant immune interferon (IFN-gamma), which activates lymphocytes to produce SIRS in vitro, was blocked by injection of levamisole or monoclonal anti-SIRS antibodies. These results show that SIRS suppresses immune responses in vivo, and suggest that suppression of PFC responses by IFN-gamma may be largely mediated by SIRS. These findings indicate that SIRS could contribute to the development of suppressed immunity in vivo.

• Authors: H W Schnaper, T M Aune
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 137 Issue 3 Pg. 863-7 (Aug 01 1986) ISSN: 0022-1767 [Print] United States
• PMID: 3088113 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Suppressor Factors, Immunologic
• soluble immune response suppressor
• Levamisole
• Interferon-gamma

Topics

• Animals
• Antibody Formation
• Erythrocyte Transfusion
• Hemolytic Plaque Technique
• Hypersensitivity, Delayed (immunology)
• Injections, Intraperitoneal
• Interferon-gamma (pharmacology)
• Kinetics
• Levamisole (pharmacology)
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Sheep
• Suppressor Factors, Immunologic (administration & dosage)