Pilus-mediated binding of bovine enterotoxigenic Escherichia coli to calf small intestinal mucins.

In this study we show that the adhesion to mucus of the enterotoxigenic Escherichia coli strains responsible for diarrhea in calves involves a bacterium-mucin recognition phenomenon in which the bacterial pili and specific mucus receptors carried by the glycoproteins (2,000 to 400 kilodalton) play a major role. An adhesion maximum was observed at a pH of less than 6 (4.75 to 5.25). The sialic acids and galactose appeared to be at least partly responsible for the attachment of K99 pili, whereas F41 pili preferentially recognized desialylated receptors. The attachment of different strains of E. coli characterized by the presence of the three main pili, K99, F41, and FY, known to be responsible for the binding of enterotoxigenic E. coli to the intestinal epithelium of the calf, was studied using Scatchard and Hill analyses. The attachment mechanism of bacteria carrying K99 pili showed positive cooperativity. FY and F41 pili recognized independent receptor sites, the first on sialylated mucus and the second on sialidase-treated mucus. Moreover, F41 pili were found to bind the native mucus according to a negative cooperativity phenomenon. Finally, the recognition sites carried by bacterial pilins may be saturated by some animal glycoprotein glycans which are therefore adhesion inhibitors.

[Schizophrenia and histocompatibility antigens]. / Schizophrénies et antigènes d'histocompatibilité.

Schizophrenias have a genetical support as it is now proved by the study of twins born from schizophrenic parents and of the adopted children of schizophrenics. The HLA typing brings an additional argument in favour of this hypothesis. After a recall of data concerning the system of tissular histocompatibility, the results are given of the HLA typing of a population of 65 schizophrenics (59 men, 6 women) including 27 hebephrenics and 38 paranoïds. The paranoïd group is clearly individualized from a genetic point of view. If 40% of the schizophrenics carry the A9 antigen versus 21,2% found in the normal population, 47,4 % of the paranoïd schizophrenics present this antigen (X2) = 12,16 p less than 0,001). The association of the two antigens A9 and CW4 is even more significant: 14,3 % of the total schizophrenic population, as opposed to 2,7 % in the normal population (X2) = 13,3 p less than 0,0005). The paranoid group reached a rate of 24,3% (x(2) = 27,3 p less than 0,0005). A subject carrier of both antigens A9 + CW4 has 11,5 times more the risk of being a paranoïd schizophrenic than a subject not possessing these two antigens.

[Schizophrenia: association of the paranoid form and antigens HLA-A9 and B5]. / Schizophrénie: association de la forme paranoïde aux antigènes HLA-A9 et B5.

30 unrelated Schizophrenic patients (15 Hebephrenic and 15 Paranoïd forms) were Typed for 14 A and 16 B Specificities by microlymphocytotoxicity. We note: 10 (5H + 5P) HLA--A1 (33.3 % / controls 23.4 %) 5 (2H + 3P) HLA--A3 (16.6 % / controls 26.2 %) 6 (5H + 1P) HLA--B8, 0 HLA--B27, 0 HLA BW16 and more specially: 10 (3H + 7P) HLA--A9 (23 + 24) 8 (2H + 6P) HLA--B5 These two last antigens are more often found in the Paranoïd patients of whom 46.6% are A9 Tcontrols: 24 %) and 40 % are B5 (controls 13.2 %. The Pc values are not significant in these too short seria but the strongly increased frequencies of A9 and B5 in the Paranoïd group seem to open a new biological aspect in the nosographic distinction of the Schizophrenia and so confirm previous results of C. L. CAZZULLO et al.