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M Porro

Publications and source records attributed to M Porro.

27 records · Page 2Linked to original sources
PubMed1985

A semi-synthetic glycoconjugate antigen prepared by chemical glycosilation of pertussis toxin by a meningococcal group C oligosaccharide hapten.

The preparation of a hybrid molecule obtained by chemical glycosilation of pertussis toxin (PT) is reported, with the purpose of obtaining a semi-synthetic glycoprotein antigen with bivalent antigenicity. The chemical glycosilation was performed using an oligosaccharide hapten derived from the purified capsular polysaccharide of Neisseria meningitidis group C. The semi-synthetic molecule was investigated by chemico-physical and immunochemical analysis. The oligosaccharide haptens appeared exposed on the surface of the carrier protein PT, since the glycoprotein inhibited the immunoprecipitate between a specific polyclonal antiserum and the native bacterial capsular polysaccharide. By contrast, the main antigenic regions recognized in the native protein PT by specific polyclonal antibodies appeared lost after the coupling procedure involving PT as the carrier protein.

Antibody Specificity↗
PubMed1983

Immunoelectrophoretic characterization of the molecular weight polydispersion of polysaccharides in multivalent bacterial capsular polysaccharide vaccines.

The molecular weight polydispersion of single antigens present in multivalent bacterial capsular polysaccharide vaccines has been characterized by an immunoelectrophoretic method. Chromatographic effluents from Sepharose gel of bacterial capsular polysaccharide vaccines were tested by fused-rocket immunoelectrophoresis and the distribution coefficient (Kd) of each polysaccharide present in the mixture was calculated. The method appeared to be efficient and reproducible. However, different Kd values were obtained by immunoelectrophoretic and chemical or physical analysis of the chromatographic effluents of each single polysaccharide component. The use of this immunoelectrophoretic procedure was extended to the potency control of multivalent meningococcal and pneumococcal polysaccharide vaccines in order to detect changes in the molecular weight polydispersion of each antigen with time.

Bacterial Vaccines↗
PubMed1980

Immunogenic correlation between cross-reacting material (CRM197) produced by a mutant of Corynebacterium diphtheriae and diphtheria toxoid.

The in vivo immunizing potency of diphtheria toxoid and formalin-treated corss-reacting material (CRM197, a nontoxic mutant protein) was compared in guinea pigs. Major antigenic differences between the two untreated proteins were also tested in rats. The results showed that diphtheria toxoid and CRM197 were equally effective immunogens, but only if the latter was treated with formalin in the same concentration (0.7% vol/vol) was that of the toxoid. Formalin treatment rendered the antigens more resistant to enzymatic proteolysis by trypsin in vitro.

Animals↗
PubMed1978

New hemolytic method for determination of antistreptolysin O in whole blood.

A new method is proposed for the determination of antistreptolysin O, based on the properties of streptolysin O. The reduced form of the toxin is hemolytic, whereas the oxidized form is not; this activity can be restored, however, by a reducing agent. Both forms maintain the capacity to bind specific antibodies. Unlike the classical method, the assay is performed on whole blood, using the patient's own erythrocytes as revealing agents. A procedure is proposed which limits the operation to a single dilution of a microvolume of blood (0.05 ml brought to 2 ml) and to the distribution of constant quantities in test tubes prefilled with different amounts of oxidized streptolysin O. After a few minutes, a reducing agent is added, and the reading is performed as in the classical technique after sedimentation of the erythrocytes. Correlation with the traditional method (r = 0.987) is evaluated on the basis of the results of samples from hospitalized patients.

Adult↗