Plasmids in Yersinia enterocolitica serotypes O:3 and O:9: correlation with epithelial cell adherence in vitro

Human isolates of Yersinia enterocolitica serotypes O:3 (biotype 4) and O:9 (biotype 3) harbored plasmids sized approximately 47 and 44 megadaltons, respectively. No such plasmids were found in "apathogenic" strains of Y. enterocolitica belonging to biotype 1. There was a positive correlation among the presence of plasmid, autoagglutination, and adherence to and toxicity for HEp-2 cell cultures; all of these properties were lost by culturing at 37 degrees C in the absence of calcium. Strains of Y. enterocolitica O:3 and O:9 cured of the plasmids showed increased invasiveness in the HEp-2 cell culture model, but no invasiveness in guinea pig eye. It is suggested that the plasmids of Y. enterocolitica primarily determine epithelial cell adherence, but may also be associated with other pathogenic properties.

Immunodeficiency associated with a deletion in the short arm of the X-chromosome

The immunocapacity of a 28-year-old mentally retarded proband and her clinically normal mother and sister, all having a deletion of the short arm of one of the X-chromosomes [46, X, del (X) (pter to 22: :p11 to qter)], was evaluated. The concentrations of immunoglobulin IgA (0 . 4 g/l), IgG (4 . 4 g/l) and IgM (0 . 2 g/l) were low in the proband. The serum IgA (0 . 9 g/l) concentration of her mother was also at the lower normal limit. The serum concentration of complement component C4 was low both in the proband (0 . 17g/l) and in her mother (0 . 18 g/l). Phagocytosis and killing of bacteria by granulocytes were normal in all of them. However, the chemotactic response of granulocytes was at the lower normal level in the patient. The in vitro responses of peripheral blood lymphocytes to the polyclonal T-clonal mitogens, PHA and Con A, were about half normal in the patient and were also decreased in her mother. The response was also decreased against PWM, to about one-sixth of the normal value in the patient and to one-half in her mother. The Con A response was decreased in the sister, while her PHA and PWM responses were normal. In contrast to these findings, the responses against the antigen-specific stimulators, PPD and oidiomycin, were normal in all subjects. Natural killer cell activity against the K-562 cell line was decreased in the patient but normal in her mother and sister. The number of B cells was at the normal limit in all subjects. The amount of E rosette-forming T lymphocytes was normal but the amount of ANAE-positive cells was decreased, especially in the proband (31%). Our results describe a new human immunodeficiency state, probably associated with X-chromosome deletion. We suggest that the short arm of the X-chromosome exerts its effect on regulatory T cells. Whether the humoral defect is connected with suppressor T cells remains to be established.

Intraembryonic origin of lymphoid stem cells in the chicken: studies with sex chromosome and IgG allotype markers in histocompatible yolk sac-embryo chimaeras

Two-day-old chick embryonic bodies were transplanted onto the area vasculosa of age-matched histocompatible blastoderms, resulting in the development of yolk sac-embryo chimaeras. Eighteen of these succeeded in hatching and became adults. Differences in the sex chromosomes and in IgG allotype between the embryo and the yolk sac were used to study the contribution of these two components to the lymphoid cell development. At 5-7 weeks of age the chimaeras proved to be completely normal in the IgM and IgG antibody production against human gamma globulin and Brucella abortus and in the lymphocyte responses to phytohaemagglutinin and concanavalin A. For the sex chromosome analyses bursa cells and specifically stimulated B and T lymphocytes were used. The latter was achieved by stimulating thymus, spleen, and bone marrow cells in vitro with anti-Ig and Con A. Only four out of 1498 mitoses analysed belonged to the sex opposite to that of the bird. Among the chimaeras eleven were marked through IgG allotypes. At the age of 3-20 weeks all eleven chimaeras showed serum IgG of the embryo allotype and none of the yolk sac type. These results, based on the use of two different markers, indicate that lymphoid stem cells in the chicken are originally derived from an intraembryonic source and not from the yolk sac.

Genetic differences in the mitogenic response of peripheral blood lymphocytes in the chicken

The mitogenic responses of chicken peripheral blood lymphocytes were compared in two partially inbred chicken lines and in their hybrids. The lymphocytes of line P chickens showed a higher phytohaemagglutinin (PHA) response than those of line V chickens and (P X V)F1 hybrids. The Con A responses were of the same magnitude in all chicken lines. The higher PHA response in line P chickens was not sex-linked, apparently was not associated with the major histocompatibility complex and it did not correlate with immunoglobulin G allotypes.

Effect of preimmunization with native and methylated carrier on class-specific anti-hapten and anti-carrier antibody response

Effects of priming with bovine serum albumin (BSA) and methylated BSA (MBSA) on the primary anti-2,4-dinitrophenyl (DNP) response were studied in the chicken. A new radioimmunoassay of class-specific antibodies (RIACA) was used to quantitate IgM and IgG antibodies against BSA and DNP. The anti-DNP antibody response after priming with BSA was dose-dependent: large doses of BSA suppressed and the smallest dose augmented it. In contrast, no dose dependence was observed between MBSA and the anti-hapten response. All doses of MBSA enhanced the primary anti-DNP antibody response of both immunoglobulin classes. No corresponding differences in anti-BSA antibodies were observed between BSA- and MBSA-primed groups. This suggests that the anticarrier antibodies as such are not the agent suppressing the anti-hapten response when large doses of native carrier are used for priming. A more probable explanation of this phenomenon is a competition between carrier-specific B cells and hapten-specific B cells for common T cells. A less obvious explanation is the generation of more helper cells or less suppressor cells when priming with MBSA than with BSA.