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Highly purified S-antigen from human, bovine, porcine and rat retina was used to ascertain the molecular weights, isoelectric points, amino-acid composition and presence of carbohydrate moieties. All S-antigen preparations comigrate to 50,000 MW on SDS-polyacrylamide gels and demonstrate microheterogeneity upon isoelectric focusing. Human S-antigen exhibits two bands at pH 5.9 and 5.6, whilst with bovine S-antigen a broad band at pH 5.9 was observed. Porcine and rat S-antigen gave four bands, focusing between pH 5.0-5.6. Two-dimensional gel analysis revealed that all the four focused porcine polypeptides migrate to 50,000 MW. Western-blot analysis following isoelectric focusing of human and porcine S-antigen showed that all polypeptide bands react specifically with polyclonal and monoclonal antibodies to S-antigen. The reasons for the apparent heterogeneity of S-antigen by isoelectric focusing are discussed. All S-antigen preparations were weakly positive for periodic acid Schiff staining, and specifically bound radiolabelled Lens culinaris lectin on Western-blot analysis. These results confirm the glycoprotein nature of S-antigen which may explain the finding of multiple bands found on isoelectric focusing. Amino-acid analysis reveals the high percentage of non-polar amino acids and may explain the apparent hydrophobic behaviour of the isolated protein.

This paper describes the application of parallel bioassay to determine the extent to which the leucocyte chemotactic activity of guinea-pig lymphokine preparations is associated with their lymphocyte mitogenic, inflammatory (increased vascular permeability) and macrophage migration inhibitory activities. A convenient test of chemotactic activity was devised whereby Coulter counter determinations were made of the number of peritoneal exudate cells passing through a Nuclepore membrane into the medium of the lower (test) compartment of a chemotaxis chamber. Symmetrical parallel line (2+2) dose assays were used to obtain potency ratio estimates of the chemotactic activity of seven lymphokine preparations whose mitogenic, inflammatory and migration inhibitory activities were already known. Statistical analysis of the results revealed a clear dissociation of chemotactic activity from mitogenic and migration inhibitory activities; but with six of the seven lymphokine preparations, a marked similarity was revealed between their chemotactic and inflammatory activities. Cytological studies showed that although the lymphokine preparations were chemotactic for different cell types, there was a preferential migration of neutrophils and the smaller mononuclear cells. The demonstration by parallel bioassay of an association between the ability of lymphokine preparations to increase vascular permeability in vivo and to promote chemotaxis of leucocytes in vitro is viewed in relation to the possible role of lymphokine in inflammatory processes.

This paper describes the application of numerical methods to the arrangement of four leishmanial strains according to their reactivity and cross-reactivity in tests of parasite agglutination, indirect immunofluorescence and passive cutaneous anaphylaxis with antisera prepared by immunization or infection of rabbits, guinea-pigs and mice. Using corresponding pools of animal sera as test 'reagents' the antigenic reactivity of the four leishmanial strains (L. enriettii, L. tropica major, L. aethiopica and L. mexicana amazonensis) was scaled by reference to end-point serum titres; and antigenic relationships between individual strain pairs were expressed as mean similarity coefficients, giving equal weight to the results of the different serological tests. Overall analysis of the results revealed that L. mexicana amazonensis and L. tropica major were the two most closely related strains, clustering with an overall similarity coefficient of 89%, whereas coefficients of similarity between other strain combinations fell between 75 and 80%. Although different sera had different discriminatory capacity for the leishmanial strains, two combinations of serum reagent and test system yielded relationships between the four strains that most closely approximated to the overall values. These were: (a) immunofluorescence tests with mouse antisera; and (b) agglutination tests with selected rabbit antisera. The results illustrate the use of a number of immunological parameters in relating micro-organisms of a given genus, and reveal a serological classification of the four leishmanial strains at variance with their geographical origin.

Disagreement persists about the phagocytic function of blood polymorphonuclear leucocytes (PMN) in rheumatoid arthritis (RA). Many of the experimental data have been generated by subjective methods of assessment. Using a radiometric assay, we found no difference in the phagocytosis and intracellular killing of Candida albicans by blood PMN from 18 patients with RA when compared with PMN from 21 healthy control subjects. We infer that the increased incidence of non-articular infection reported in RA is not related to impaired phagocytic function of blood PMN.

Fifty-two patients with retinal vasculitis--26 with idiopathic disease and 26 with associated systemic inflammatory disease--were followed up for periods ranging from six months to 12 years. The aim of the study was to determine the relationship between relapse of uveitis, visual outcome, and the occurrence of circulating immune complexes (CIC) and antiretinal antibodies. In a total of 69 relapses, CIC were increased in one-third of patients and antiretinal antibodies in one-half. In those 34 patients who expressed antiretinal antibodies 27 (79%) of the relapses were characterised by antiretinal antibodies in the absence of raised CIC levels (p less than 0.01). These findings support our previous hypothesis that CIC may have a protective role in autoimmune retinal vasculitis and that antiretinal autoimmunity is of pathogenetic importance in relapse. In individual patients the visual outcome was not related to the number of relapses or to the CIC-autoantibody pattern, suggesting the operation of additional features which merit identification.

The decrease in Fc-receptor-positive cells that occurred during a 6 h incubation of resident and elicited guinea-pig macrophages was partly abrogated when lymphokines were present in the culture. When the same lymphokine preparations were tested on C3b receptor-expression they preferentially sustained the percentage of C3b rosettes formed by resident rather than elicited macrophages. This lymphokine-induced maintenance of Fc and C3b rosettes by cultured macrophages may have been due to an inhibition of receptor release or an increase in receptor synthesis. Supernatants from cultured macrophages contain shed Fc and C3b receptors which inhibit rosette formation by other macrophages. From the demonstration that culture supernatants from both lymphokine-treated and untreated macrophages significantly inhibited Fc and C3b rosette formation by freshly obtained macrophages it seems that the shedding of Fc and C3b receptors is not modified by lymphokines. The maintenance of Fc and C3b rosettes by lymphokines was inhibited by treatment of the macrophages with cycloheximide, suggesting that the lymphokine effect was due to an increase in synthesis de novo of the Fc and C3b receptors. The lymphokine-inducing antigens, BGG and PPD, and control lymphokine preparations were devoid of receptor modifying activity. The reduction in the percentage of Fc rosettes after 6 h culture appears to be due to a loss of Fc receptors for IgG1. Although lymphokines partly inhibited this effect they could not prevent the loss of these receptors following 24 h culture, unlike their action in augmenting the expression of Fc receptors for IgG2. These findings suggest that a selective enhancement of Fc receptor synthesis by lymphokines may modify the functional activities of macrophages.

Porcine aortic vascular endothelial cells were grown to confluence on microporous PTFE membranes and incorporated into a two-compartment chemotaxis assembly. Human peripheral blood mononuclear cells (20-25% monocytes) were placed in the upper compartment and zymosan-activated human serum (ZAHS) as chemoattractant in the lower compartment. Over a 3 h period monocytes migrated across the endothelialized membrane and adhered to a collecting filter sited in the lower compartment. Addition of ZAHS to the cell suspension in the upper compartment virtually abolished the migration response whilst only minimal leucocyte migration was supported by the bare unendothelialized PTFE membrane. The extent of transendothelial monocyte chemotaxis was dependent upon the concentration of chemoattractant in the lower compartment and upon the cell density of the suspension containing monocytes. A confluency test of fluid flow across the endothelialized filter showed that monocyte migration could take place without disturbing endothelial barrier function. The culture system is easy to assemble and the method provides experimental versatility.

This study shows how infection of CBA mice with L. tropica can be manipulated so as to mimic the principal features of both subclinical and self-healing cutaneous leishmaniasis in man. CBA mice were infected with graded inocula of L. tropica promastigotes. The pattern of primary infection was found to be dependent on dose of infecting organisms: mice given low dose inocula (10(2), 10(3)) developed subclinical infections; those given high dose inocula (10(4), 10(5), 10(6)) developed overt, clinical lesions. Size and duration of lesions, and antibody production were directly proportional to dose; delayed hypersensitivity responses were inversely proportional to dose. Protective immunity to challenge infection was induced by both subclinical and clinical infection; and was manifest both during and after the healing stages of primary lesions. Protective immunity was also induced by artificial immunization with sonicated promastigotes in adjuvants but was only manifest if the challenge dose was not too large. The course of challenge infections differed depending on the method of immunization, i.e. whether by infection or artificial immunization. Lymphoid cells from immune CBA mice conferred protection on recipient syngeneic CBA mice against challenge infection; serum from immune mice did not, but suspension of immune peritoneal cells in immune serum enhanced their protective capacity. The experimental induction of protective immunity by low-dose infection, without a clinical allergic response at the site of inoculation, is of importance in designing an immunoprophylactic approach to human leishmaniasis.

This paper summarises the principal immunopathological mechanisms which may underlie ocular inflammation and draws attention to how autoimmune reactions may be regulated by idiotypic networks of the immune system. The study of autoimmunity in inflammatory eye disease is illustrated by our current investigations of retinal vasculitis in man and of experimental autoimmune uveoretinitis in rodents where three lines of evidence indicate that immune complex formation may be a compensatory host response to the development of antiretinal autoimmunity. In discussing immunological implications of these results we suggest that retinal inflammation in antiretinal autoimmunity is limited by a protective anti-idiotypic antibody response and that retinal disease arises when this compensatory response is improperly balanced. The clinical implications of this reasoning include the identification of patients at risk of relapse of ocular disease and the development of therapeutic methods for restoring an imbalanced anti-idiotypic autoimmune response towards normality.

In-vitro tests of cell-mediated immunity were performed using blood obtained from subjects with unexplained hepatitis following halothane anesthesia to determine whether sensitization to potentially antigenic products of halothane metabolism might exist. Both lymphocyte transformation and leukocyte migration-inhibition tests were undertaken in the presence of trifluoroacetylated human serum albumin. All tests in the presence of these potential antigenic complexes were negative. The results support the view that cell-mediated hypersensitivity to trifluoroacetylated proteins does not contribute to the pathogenesis of hepatic dysfunction following halothane anesthesia.

Longtern monolayer cultures of cells derived from explants of 21 normal and 31 rheumatoid synovial tissue specimens were studied and shown to be morphologically heterogeneous. The cultures were defined according to their cell size and their buoyant density as determined by separation on Ficoll density gradients. The investigations demonstrate that changes in these populations occurred with each passage of the cell lines. These findings emphasize the importance of using cultures of the same cultural age and passage for any comparative s tudy. The techniques described are useful for separating and defining the populations present in synovial tissue tissue cultures.

This paper describes the histopathology of chronic tuberculin-type hypersensitivity reactions in the normal canine and malignant human prostate. Seven dogs were sensitized by injection of Freund's complete adjuvant and the histological response to the subsequent intra-prostatic injection of 6 mg tuberculin PPD was documented. A chronic mononuclear cell prostatis persisted for 4 weeks and was accompanied by paracortical distension and follicular hyperplasia in regional lymph nodes. Six patients with carcinoma of the prostate were given multiple intraprostatic injections of BCG, which induced a chronic mononuclear cell prostatitis with some evidence of tumour-cell necrosis. The study indicated that the prostate can support chronic cell-mediated allergic reactions to extrinsic antigens and that intra-prostatic injections of BCG can be administered without harmful effects to patients with malignant prostatic disease.

Abnormalities of lymphocyte proliferation in chronic hepatitis B virus infection are well documented, although the underlying mechanisms are poorly understood. To determine whether these defects may be secondary to disordered lymphokine production, we have simultaneously assayed interleukin-1 and interleukin-2 production in 31 chronic carriers of the hepatitis B virus. Supernatants from mononuclear cells cultured both in the presence and absence of lipopolysaccharide contained significantly increased quantities of interleukin-1 activity in patients compared with normal controls (p less than 0.01). Lysates of monocytes from patients also contained more interleukin-1 than those of controls (p less than 0.05) in the presence of lipopolysaccharide or silica, or both. These results indicate that interleukin-1 production is markedly elevated in patients with chronic hepatitis B virus infection, whereas in contrast, interleukin-2 production was found to be reduced in these patients (p less than 0.01). As one of the biological properties of interleukin-1 is to stimulate fibroblasts to produce collagen, the relationship between fibrosis in the liver biopsy specimen and interleukin production was examined. There was a highly significant correlation (p less than 0.001) between interleukin-1 production and the severity of fibrosis, suggesting that this lymphokine may be closely related to the development of cirrhosis in such patients.