Modulation of CD4 antigen expression on the lymphocyte surface by immunosuppressive acidic protein in cancer patients.
The immunomodulatory effect of human immunosuppressive acidic protein (IAP) on lymphocyte surface antigens was investigated. IAP inhibited lymphocyte responses to phytohemagglutinin in a dose-dependent manner. By flow cytometry, using fluorescein-isothiocyanate-labelled antibodies, the mean fluorescence intensity on peripheral blood lymphocytes (PBLs) decreased for CD4, slightly decreased for CD3 but showed no change for the CD8 and T cell receptor alpha-beta antigens in the presence of IAP. This CD4 antigen modulation by IAP was observed in PBLs freshly isolated from patients with unresectable cancer but not in those isolated from patients with resectable tumor or from healthy volunteers. The modulation of the CD4 antigen by IAP on the lymphocyte surface was correlated with an increment of serum IAP levels in cancer patients. The CD4 modulation could be induced in PBLs from healthy volunteers by culturing them with IAP in vitro. It is suggested that IAP may play a role in cancer-related immunosuppression through the down-modulation of the CD4 antigen on the lymphocyte surface.
Yamaguchi
Y
Y
Department of Surgery, Hiroshima University, Japan.
Miyahara
E
E
Funakoshi
M
M
Takashima
I
I
Kawami
H
H
Sato
Y
Y
Toge
T
T
D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology; D009363:Neoplasm Proteins / Q000494:pharmacology*; D009369:Neoplasms / Q000276:immunology*
D017252:CD3 Complex; D015704:CD4 Antigens; D009363:Neoplasm Proteins; C030193:immunosuppressive acidic protein