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Anti-lymphocytic antibodies (ALA) have been described in a variety of autoimmune disorders. We have investigated the presence of ALA in autoimmune chronic active hepatitis (aCAH) starting in childhood. Using a modified Terasaki technique ALA were found in 17 of 18 patients with aCAH but in only one of 15 patients with alpha-1-anti-trypsin deficiency or Wilson's disease and three of 27 aged-matched healthy controls (P < 0.0005 for both). Sera from 12 patients with uncontrolled aCAH had significantly higher cytotoxicity values than sera from six children with inactive disease (P < 0.01). ALA were directed to T but not B lymphocytes and were not reactive with specific HLA antigens. No preferential killing was observed against CD4 or CD8 positive T lymphocytes. Characterization of ALA revealed them to be cold-reactive IgM. The possible role of ALA in aCAH is discussed. [ABSTRACT FROM AUTHOR]

Purified IgG from murine alloimmune sera directed against class 1 products from the major histocompatibility complex of the mouse, could bind to the β-adrenoceptors and stimulate contractile activity of myocardium. Immune IgG inhibited the binding of (-) ³H-DHA to β-adrenoceptors of mouse myocardial membranes behaving as a competitive inhibitor, Moreover, immune IgG induced positive inotropic and chronotropic effects on isolated mouse atria. These effects could be blocked by β-adrenoceptors antagonists. Data prove that immune IgG directed against specific alloantigens are able to recognize the β-adrenoceptors and mimic the stimulation of the β-adrenoceptor agonist. [ABSTRACT FROM AUTHOR]

Porcine hyaline articular cartilage (HAC) has been used to investigate the interaction of bovine serum albumin (BSA) and anti-BSA with articular collagenous tissues in vitro. There was a marked retention of 125I-labelled BSA by plugs of HAC (a) exposed to rabbit anti-BSA for 1-2 h at 37°C prior to a similar incubation with the antigen, or (b) exposed to the antigen and then to antibody. The specifically retained radiolabelled BSA was localized in or at the articular surface of the plugs. In the absence of specific antibody a relatively small amount of the antigen was retained. Exposure of HAC to multiple cycles of antibody and antigen treatment resulted in an increased retention of the 125I-BSA. There was a concomitant increase in the retention of the anti-BSA and the capacity of the treated plugs to fix complement. The forces that maintained the labelled antigen in the tissue were not readily reversed by excess unlabelled BSA. Pre-formed, soluble BSA/anti-BSA complexes did not appear to penetrate the tissue unless the HAC was first exposed to anti-BSA. The results suggest that the antibody-mediated, surface oriented retention of 125I-BSA results from the formation of immune complexes in the tissue. [ABSTRACT FROM AUTHOR]

In vitro human monocytes from normal blood donors ingest red blood cells infected with Plasmodium falciparum more efficiently than normal red blood cells (NRBC). The phagocytic activity of human monocytes for infected red blood cells (IRBC) is greatly enhanced by the addition of immune sera obtained from individuals living in areas with endemic malaria. In contrast, the addition of sera obtained from individuals recovering from a first infection, or pooled normal sera, does not result in increased phagocytosis of IRBC. The phagocytosis enhancing activity of immune sera is associated with the IgG fraction and IgG depleted sera do not stimulate phagocytosis. Enhanced immune serum mediated phagocytosis occurs as a result of opsonization of IRBC. This was demonstrated by experiments in which monocytes or IRBC were preincubated with immune serum prior to the phagocytic assay. The opsonic activity could be absorbed by IRBC but not by NRBC. The opsonization of IRBC and subsequent phagocytosis were also dependent on the stage of development of the intracellular parasite. IRBC containing schizonts and trophozoites were preferentially phagocytosed as compared with ring forms. The role of malaria induced surface alterations and/or malaria surface antigens in the opsonization of IRBC by immune sera is discussed. These experiments suggest that phagocytosis of P. falciparum IRBC by monocytes may play a role in the immune elimination of malaria infection in humans. [ABSTRACT FROM AUTHOR]

We have studied the effect of dialysates from lung cancer homogenates to alter both the expression of complement (C3b) receptors per se and also to inhibit leucoattractant-induced enhancement of complement rosettes on monocytes from healthy individuals. Enhancement and enhancement-inhibition by tumour extracts were compared with material derived from normal lung excised some distance from the tumour. There was no significant difference between tumour homogenate (TH) and normal lung homogenate (NLH)in terms of enhancement of complement rosettes per se. In contrast, TH produced a dose- and time-dependent inhibition of leucoattractant-induced enhancement of C3b rosettes which was significantly different from that obtained with NLH. This enhancement-inhibition was observed with four undifferentiated, four squamous and three adenocarcinomas of lung. The degree of enhancement-inhibition was not related to the type of tumour or varying accompanying histological features such as necrosis and the degree of infiltration with inflammatory cells. Following gel filtration on Sephadex G-50 each type of cancer gave a major peak of inhibitory activity which eluted with molecules having an apparent molecular size of approximately 3.000 daltons. A second larger peak (8,000-10,000 daltons) was also detectable with extracts from the undifferentiated and adenocarcinomas. These results support previous findings, mainly from experimental animals, indicating that "anti-macrophage/monocyte principles' are elaborated from certain tumour types. [ABSTRACT FROM AUTHOR]

Antibodies in human sera against four different antigens of human spermatozoa discovered by means of an indirect two-layer immunofluorescence technique (IFT) were characterized by determination of the class of immunoglobulins to which they belonged. A three-layer IFT using monospecific antisera against human IgG, IgA or IgM as the second layer was employed together with fractionation of sera on Sephadex G-200 or DEAE-cellulose followed by testing of the concentrated pools in a two-layer IFT. The study revealed that antibodies against the antigen in the front part of the acrosome were primarily IgM and those against the antigen in the tail primarily IgG. Antibodies against antigens in the equatorial segment and the postnuclear cap showed a varying predominance of these two immunoglobulins. Spermatozoal antibody as IgA was found only in small amounts. [ABSTRACT FROM AUTHOR]