An outbreak of streptococcal sore throat and rheumatic fever in a Royal Air Force training camp; significance of serum antibody to M-associated protein

A large outbreak of streptococcal sore throat in a Royal Air Force Training Camp resulted in five cases of rheumatic fever among the 16- to 18-year-old apprentices, and one case in a 33-year-old airman. The most prevalent type of group A streptococcus isolated from throat swabs was M-type 5 and there was serological evidence that at least four of the rheumatic fever (R.F.) cases were due to this type.Among the patients with uncomplicated throat infection the anti-streptolysin O (ASO) and anti-deoxyribonuclease B (anti-DNAase B) responses were in general rather low, even where there was evidence of protective antibody against type 5. However, a combination of the results of the ASO and anti-DNAase B tests gave an estimate of the extent of streptococcal infection 15-25% higher than did either test alone.The titres of antibody to M-associated protein (MAP) were >/= 60 in all the R.F. patients, and in about 50% of the other patients with ASO titres >/= 200. This figure is unusually high compared with data from several other outbreaks of streptococcal infection due to different serotypes and also greatly exceeds comparable figures for cases of sporadic sore throat and acute glomerulonephritis.

Antibody responses to group A streptococcal infections in the hamster

The immune response after streptococcal infections of the skin and of the joints was studied in an experimental animal model. Hamsters were challenged intradermally or intra-articularly with different streptococcal serotypes, and antibodies for streptolysin O (ASO), deoxyribonuclease B (anti-deoxyribonuclease B), and group A carbohydrate (anti-group A CHO) were determined. After a single injection at either site, 7 of 48 animals (14%) developed group A-CHO antibodies; however, none of the animals developed detectable levels of ASO or anti-deoxyribonuclease B. After repeated infections of the skin or joint, anti-deoxyribonuclease B antibodies were detectable in 13% (4 of 30) and 30% (5 of 17) of the animals, respectively. Elevations of ASO occurred after repeated joint infections in 4 of 16 animals (25%), whereas none of 30 hamsters repeatedly infected intradermally developed antibodies against streptolysin O. For all three antibodies tested, elevated levels were more frequently noted after repeated joint infections than after repeated skin infections with the same streptococcal serotype. These data, similar to ones previously noted in human impetigo, indicate that ASO responses are feeble after streptococcal skin infections and that the site of infection per se, rather than the infecting strain, appears to be responsible for this poor response.

Impaired lymphocyte transformation in intestinal lymphangiectasia: evidence for at least two functionally distinct lymphocyte populations in man

Intestinal lymphangiectasia is a disease characterized by hypoproteinemia and edema resulting from protein-losing gastroenteropathy secondary to abnormal intestinal lymphatics. Immunologic abnormalities associated with this disease include hypogammaglobulinemia, lymphocytopenia, skin anergy, and impaired allograft rejection. In the present study, the in vitro blastogenic transformation of lymphocytes from 12 patients with intestinal lymphangiectasia was assessed in order to gain insight into the mechanism of the cellular immune defect in this disease. Peripheral blood lymphocytes from patients with intestinal lymphagiectasia showed impaired in vitro transformation to nonspecific mitogens, specific antigens, and allogeneic cells when compared to equal numbers of cells from normal individuals. Patients with the most deficient in vitro reactivity tended to have the lowest serum albumin concentration and the lowest absolute lymphocyte count. Lymphocytes obtained from chylous effusions in each of the four patients studied transformed more vigorously than peripheral blood cells from the same patients. These results may be explained by the loss of recirculating, long-lived lymphocytes into the gastrointestinal tract, resulting in a relative depletion of the population of lymphocytes necessary for in vitro blast transformation. This disease thus represents a clinical analogue of animals with experimental thoracic duct drainage, and provides evidence for the existence, in man, of two functionally distinct lymphocyte populations. In addition, these findings establish a new mechanism of impaired delayed hypersensitivity and defective in vitro lymphocyte transformation, i.e. the gastrointestinal loss and consequent depletion of the long-lived, recirculating population of lymphocytes from the peripheral lymphocyte pool.

Detection of cholesterol in cell membranes by use of bacterial toxins

A method is described for the detection of cholesterol in membranes from erythrocytes, mycoplasmas, and bacterial cells by a ferritin-labeling technique. Membranes treated with cereolysin, a bacterial hemolysin which specifically binds to cholesterol, and then treated with ferritin-antitetanolysin, were specifically ferritin-labeled for cholesterol. A similar antigen-antibody system, streptolysin O-ferritin-antistreptolysin, was also used successfully with erythrocyte membranes. There was an uneven distribution of ferritin in erythrocyte membranes suggesting that the distribution of cholesterol may not be entirely random. Mycoplasma gallisepticum was intensely labeled, but Acholeplasma laidlawii with or without cholesterol in the membranes was not labeled, suggesting an unusual location for cholesterol in A. laidlawii membranes. As controls, two of three species of bacterial membranes lacking cholesterol were not ferritin-labeled.

Influence of species of origin of red blood cells on in vitro inhibition of streptolysis O by serum lipoproteins

High non-specific anti-streptolysin·titres (lipoprotein-dependent) showed different values in the same sera when tested with various kinds of erythrocytes. With rabbit erythrocytes, low non-specific titres were obtained, in contrast to red blood cells from sheep, man, ox, horse, pig and rat. In contrast, high specific anti-streptolysin·titres did not vary much with the kind of red blood cells used.

Induction and suppression of the cytotoxic activity of human lymphocytes in vitro by heterologous anti-lymphocyte serum

Heterologous anti-lymphocyte sera were demonstrated to induce a cytotoxic potential in normal non-immunized human lymphocytes against allogeneic fibroblast target cells. The cytotoxicity-inducing capacity was restricted to certain dilutions of anti-lymphocytic serum above and below which no cytotoxic effect was obtained. This optimal concentration shifted towards higher dilutions in sera taken late during the immunization course. The antisera were shown to stimulate the DNA-synthesis in lymphocytes and to aggregate the lymphocytes to the target cells. The DNA-synthesis and the aggregation as well were maximal at the same dilution of anti-lymphocytic serum which induced cytotoxicity. No cytotoxic effect was demonstrable on sheep fibroblasts. It is, therefore, suggested that the anti-lymphocytic serum antibody induces lymphocyte-mediated cytotoxicity against allogeneic fibroblasts in a two step manner: it stimulates the lymphocytes into a cytotoxic state; it aggregates the human lymphocytes to the human fibroblasts by virtue of its bivalent structure.

Anti-lymphocytic serum was also found to suppress the cytotoxic activity of lymphocytes induced by various non-specific agents, such as phytohaemagglutinin, streptolysin O and anti-lymphocytic serum itself. The mechanism for this inhibition is extensively discussed and it is suggested that anti-lymphocytic serum suppresses the reaction by coating the lymphocytes, thereby preventing the intimate contact between effector and target cell. A similar mechanism may operate in vivo and could be a partial explanation of the in vivo immunosuppressive effect of anti-lymphocytic serum. Purified 7S γ-globulin possessed all activities of the whole antiserum.