Lack of a role of monocytes in the inhibition by monoclonal antibodies to monomorphic and polymorphic determinants of HLA class I antigens of PHA-P-induced peripheral blood mononuclear cell proliferation.
This study aimed at characterizing the mechanism(s) underlying the regulatory role of distinct determinants of HLA Class I antigens in PHA-P-induced T cell proliferation and the involvement of monocytes in this phenomenon. The anti-HLA-A2,A28 monoclonal antibodies (MoAb) CR11-351, the MoAb Q6/64 to a determinant restricted to the gene products of the I antigens HLA-B locus, and the MoAb CR10-215 and W6/32 to distinct monomorphic determinants of HLA Class I antigens were found to inhibit PHA-P-induced peripheral blood mononuclear cell (PBMC) proliferation in a dose-dependent fashion. The inhibition is specific and reflects neither inhibition of PHA-P binding to cells nor a toxic effect of the anti-HLA Class I MoAb. The latter differed in the concentration required to induce inhibition, in the influence of the concentration of PHA-P used as mitogen, in the differential effect on the donors used as a source of PBMC, and/or in the requirement of the Fc portion to induce inhibition. At variance with the information in the literature, the inhibitory effect of anti-HLA Class I MoAb on PHA-P-induced PBMC proliferation neither reflected their interaction with accessory cells nor was mediated by suppressor factors released by monocytes stimulated with PHA-P in the presence of anti-HLA Class I MoAb. Therefore, the regulatory role of HLA Class I antigens in T cell proliferation is not likely to be mediated by monocytes and/or factors released from them, but may reflect an involvement of these molecules in T cell activation pathways.
De Felice
M
M
Istituto di Oncologia Clinica e Sperimentale, Facoltà di Medicina e Chirurgia di Catanzaro, Università di Reggio Calabria, Italy.
Turco
M C
MC
Corbo
L
L
Carandente Giarrusso
P
P
Lamberti
A
A
Valerio
G
G
Temponi
M
M
Costanzo
F
F
Ferrone
S
S
Venuta
S
S
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D018801:CD2 Antigens; D017252:CD3 Complex; D000939:Epitopes / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D008213:Lymphocyte Activation; D009000:Monocytes / Q000502:physiology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011971:Receptors, Immunologic / Q000276:immunology; D015375:Receptors, Interleukin-2 / Q000032:analysis; D050378:T-Lymphocytes, Regulatory / Q000502:physiology
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D017252:CD3 Complex; D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D007376:Interleukin-2; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2