Biomedical subjects
Publications and source records attributed to J Pillot.
With immunofluorescence staining, Fc (gamma) receptors were found on groups A, C, and G streptococci and never on pneumococci or on groups B, D, H, or K streptococci.
Serum and intestinal secretory IgA (sIgA) were investigated in control subjects and patients with alcoholic cirrhosis of the liver. Intestinal secretions were sampled by intraluminal perfusion with a balloon catheter. Monomeric IgA and sIgA were assayed by reversed radial immunodiffusion and nephelometry after separation by Ultrogel column filtration. High levels of serum sIgA were found only in patients with severe cirrhosis accompanied by jaundice. The intestinal rate of secretion of sIgA measured in these patients was significantly lower than that observed in either controls or the patients with compensated cirrhosis. Such an intestinal sIgA deficiency, which could be explained either by a fall in small intestinal immunocyte synthesis or by a defect in the transenterocyte transport system, could be partially responsible for the high incidence of intestinal infection observed in severe cirrhosis.
Structural analysis of purified IgG kappa h and IgG kappa n molecules of DA myeloma paraproteins indicated that the two IgG had different electrophoretic mobility and that L-kappa h had an unusually heavy m.w. (30,000). Peptide mapping showed the existence of additional peptides in the L-kappa h map when compared to the L-kappa n map. Total amino acid analysis showed that L-kappa h contained two additional cysteine residues and certain other amino acids than L-kappa n contained. Sequence of the first 25 NH2-terminal amino acids showed differences at positions 4, 5, 15, 18, and 21, but both L-kappa h and L-kappa n belong to the same V kappa IV subgroup. IgG kappa n but not IgG kappa h reacted with anti-gamma 1 antiserum, indicating that H chains of these two paraproteins were also different. Sera from rabbits immunized with IgG kappa n or IgG kappa h, and rendered specific for idiotypic determinants by appropriate absorption, were used for idiotype characterization of these components. Immunodiffusion, immunoelectrophoresis, and direct hemagglutination demonstrated that IgG kappa h and IgG kappa n cross-reacted partially. Inhibition tests disclosed that the main anti-idiotypic antibody was directed against a conformation structure of the complete IgG kappa h molecule, whereas cross-reaction was due to partial idiotypic similarity between H chains of the IgG kappa h and IgG kappa n. In addition, each of these paraproteins seemed also to bear private idiotypes on their H and L chains.
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At the onset of hepatitis B and more generally in some other types of this infection implying active replication of hepatitis B virus, HBe Ag is detected in the serum as macromolecular complexes with more or less masked epitopes. At the same time, HBe Ag appears bound to HBs Ag as shown by a radioimmunological assay on solid phase, implying anti-HBs and anti-HBe specificities in the same test.
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Two apparently homogeneous electrophoretic bands were found in the serum of a patient (DA) with multiple myeloma. These M-components were identified as IgA-lambda and IgG-kappa paraproteins bearing different idiotypic determinants. Further analysis of the L chains showed that the lambda-chain was homogeneous but the kappa-chain could be separated by SDS-polyacrylamide gel electrophoresis into two different bands. Both of them were associated with gamma-chains but one (termed kappa n) had normal m.w. (24,500) whereas the other (termed kappa h) was larger (m.w. 30,000). Sugar content of the two DA IgG, as determined by anthrone reaction, was similar in DA IgG kappa n (0.73%) and in DA IgG kappa h (1.1%), clearly demonstrating that the difference in m.w. was not due to a large sugar chain. Furthermore, the peptide map of the kappa h chain included nine peptides absent in those of four other control kappa-chains. Sequence analysis showed that the first 25 N-terminal amino acids of the kappa n differed from those of the kappa h chain at positions 4, 5, 15, 18, and 21. Thus the two kappa-chains had different framework regions.
A simple method, allowing easy detection of abnormally increased sIgA levels is described. It consists in quantitation of combined SC by gel double diffusion, using appropriate anti-SC immune sera. The technical conditions, locating the threshold of sensitivity of precipitation at about 25 microgram/ml, a value higher than that found in normal sera, were established. Comparison with other classical methods (SRID, ELISA and IHA) emphasizes the validity and simplicity of the technique which has shown convenient whenever a large number of sera have to be tested.
Klebsiella pneumoniae ribosomal preparations protect mice immunized by the subcutaneous route against an intraperitoneal challenge of 100 50% lethal doses. The minimal protective doses are 5 and 0.4 micrograms of proteins for preparations extracted from strains of capsular serotypes 1 and 2, respectively. This difference in protective activity is also found in bacteria killed by Formalin. The protective activity of these preparations is not diminished by their purification on sucrose gradient, which eliminates most of the membrane vesicles which are visible by electron microscopy. The use of four strains of K. pneumoniae belonging to capsular serotypes 1 and 2 allowed us to show that the immunoprotective capacity of the ribosomal preparations was specific to the capsular serotype of the origin strain. This was confirmed by experiments in which the serum of immunized mice was transferred passively. The experimental data favor the presence in the ribosomal preparation of antigens belonging to the bacterial surface and resisting elimination by ultracentrifugation on sucrose gradient. Those surface antigens (possibly capsular polysaccharide) at least play a role in the orientation of the specificity of the protection induced by the ribosomal preparations.
Secretory IgA (sIgA) were searched in 60 sera of healthy blood donors and in 1 590 sera of subjects having various diseases. 20 percent of these subjects showed an increased amount of sIgA in their sera. The only subjects presenting a constant increase (sometimes more than 20 fold the normal amount) were people with liver diseases. Quantitation of sIgA, in relation with the determination of the IgA/transferrin ratio (IgA/T) in sera, showed an important difference between Laennec's cirrhosis on one hand and virus hepatitis or post-hepatitic cirrhosis on the other. In Laennec's cirrhosis a moderate increase in sIgA went with a strong elevation of the IgA/T ratio, the latter being proportional to the degree of evolution of the disease. In virus hepatitis, the sIgA amount was largely increased while the IgA/T ratio remained at a normal value.
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