Antibody induced cell-mediated cytotoxicity. Studies of human alloantibodies in a micro-plate-test

Cytotoxic immune response of puppies to feline sarcoma virus induced tumors

The cytotoxic immune response of puppies to feline sarcoma virus induced tumors was studied. Neonatal puppies were compared with adolescent dogs. Three different types of cytotoxicity were investigated: complement dependent cytotoxicity, T-cell-mediated cytotoxicity and antibody dependent cellular cytotoxicity. The relationship between the spontaneous regression of the sarcoma and the development of the immune system of the puppies is discussed.

Cytotoxic effects of activated human monocytes and lymphocytes to anti-D-treated human erythrocytes in vitro

Incubation of human monocytes, derived from peripheral blood, with cell-free supernatants from mixed lymphocyte cultures resulted in morphological and functional changes in the mature macrophages. Activation of monocyte-derived macrophages by these factors resulted in a significant increase in their capacity to lyse anti-D-treated human erythrocytes. The lytic activity of both normal and activated macrophages appeared to be independent of erythrophagocytosis. T lymphocytes activated by either allogeneic cells or the mitogen phytohaemagglutinin were not cytolytic to treated erythrocytes even at high effector to target cell ratios.

HLA-D restriction of the macrophage-dependent response of immune human T lymphocytes to PPD in vitro: inhibition by anti-HLA-DR antisera

The response of T cells from sensitized individuals to low doses of PPD in vitro is macrophage-dependent. By testing different allogeneic combinations of macrophages and T lymphocytes, it was found that an optimal response required that antigen be presented by macrophages sharing at least one of the HLA-D determinants of the T cell donor. Antisera recognizing HLA-A, -B or -DR antigens were found to be able to inhibit this proliferative response. The anti-HLA-DR antisera were found to exert their inhibitory effect only when directed towards an antigen shared by the donors of the T lymphocytes and the macrophages. Anti-HLA-A and -B sera, however, had an inhibitory effect when reactive with the responding T lymphocytes, irrespective of their reactivity with the cooperating macrophages. It is concluded that an optimal secondary response of in-vivo-immunized T lymphocytes to PPD requires the combined recognition of the antigen and 'self' membrane structures encoded by the HLA-D locus.

Antibody-dependent and direct lymphocyte-mediated cytotoxicity in patients on hemodialysis

Twenty-two patients on chronic hemodialysis were tested for direct lymphocyte-mediated cytotoxicity (DCML) and antibody-dependent lymphocyte-mediated cytotoxicity (LALI) against selected panels of normal donor lymphocytes. The DCML reaction was only positive in patients who had received blood transfusions within the two or three months prior to testing. Thus this reaction has limited value in practice as a parameter for presensitization. The use of third-party effector cells and of target cells precoated with antibody in the LALI reaction was evaluated, and it is advocated that effector cells from the patient investigated and direct application of patient serum to reaction mixtures should be preferred in order to avoid false negative reactions. In patients who had once manifested lymphocytotoxins, LALI disclosed a much broader reactivity than seen with a conventional complement-dependent cytotoxicity technique (CDC), whereas in this study patients who had never developed cytotoxins were also negative with the LALI technique. It is concluded that a positive LALI cross-match, in spite of a negative CDC cross-match, will be a common finding in donor-recipient combinations where the recipient has preformed cytotoxins. The effect of this on subsequent graft prognosis needs further clarification.