Pneumococcal surface protein A of invasive Streptococcus pneumoniae isolates from Colombian children.

Pneumococcal surface protein A (PspA) elicits protection in mice against fatal bacteremia and sepsis caused by genetically diverse pneumococci and protects against carriage and lung infection. We determined the PspA families of invasive isolates of Streptococcus pneumoniae recovered from Colombian children <5 years of age. That 97.5% of Colombian isolates belong to PspA families 1 and 2 supports the hypothesis that a human PspA vaccine covering a few PspA families could be broadly effective.

Expression of class 5 antigens by meningococcal strains obtained from patients in Brazil and evaluation of two new monoclonal antibodies.

Determining the profile of antigen expression among meningococci is important for epidemiologic surveillance and vaccine development. To this end, two new mouse monoclonal antibodies (MAbs) have been derived against Neisseria meningitidis proteins (class 5). The MAbs were reactive against outer membrane antigens and were bactericidal. Selected anti-class 5 MAbs [(5.1)-3E6-2; (5.3)-3BH4-C7; (5.4)-1BG11-C7; (5.5)-3DH-F5G9 also 5F1F4-T3(5.c)], and the two new monoclonal antibodies C14F10Br2 (5.8) and 7F11B5Br3 (5.9), were then tested against different meningococcal strains, (63 strains of serogroup A, 60 strains of serogroup C (from 1972 to 1974); and 136 strains of serogroup B (from 1992) meningococci). Our results demonstrated that the expression of class 5 proteins in the N. meningitidis B Brazilian strains studied is highly heterogeneous. The serotypes and subtypes of B:4:P1.15, B:4:P1.9, B:4:P1.7, B:4:P1.3, B:4:P1.14, B:4:P1.16, B:4:NT, and B:NT:NT were detected in N. meningitidis B serogroups. The strains C:2a:P1.2 and A:4.21:P1.9 were dominant in the C and A serogroups, respectively. Serogroup B organisms expressed the class 5 epitopes 5.4 (18%), 5.5 (22%), 5.8 (3.6%), 5.9 (8.0%) and 5c (38%). Serogroup C expressed class 5 epitopes 5.1 (81%), 5.4 (35%), 5.5 (33%) and 5.9 (5.0%); and serogroup A showed reactivity directed at the class 5 protein 5c (47%); and reactivity was present with the new monoclonal antibody, 5.9 (5.5%). We conclude that the two new MAbs are useful in detecting important group B, class 5 antigens, and that a broad selection of serogroup B, class 5 proteins would be required for an effective vaccine based on the class 5 proteins.

[Serotypes of meningococci isolated in the USSR and the Republic of Cuba]. / Serotipy meningokokkov, vydelennye v SSSR i Respublike Kuba.

The results of serotyping of 101 meningococcal strains isolated in the Soviet Union and 23 strains isolated in the Republic of Cuba are presented. Typing within groups was carried out by Frasch's method in the double diffusion test in gel. For this purpose serotype antigens were prepared from each strain. These antigens were used in the test only after their purification by ultracentrifugation. In all cases the prevalence of serotype 2 was revealed. A great number of Cuban strains contained a wide spectrum of type antigens of both protein and lipopolysaccharide nature. Serotype antigen 15 occurred in meningococci isolated both in the USSR and in Cuba. In most cases type 15 occurred in combination with types 2 and 8. The comparison of the results obtained in the serotyping of meningococci isolated in situations, nonepidemic (USSR) and epidemic (Cuba) for serogroup B, gives no grounds for considering type 2 as the "marker of virulence". Probably, this problem will be solved by the differentiation of subtypes within type 2. Attention should be paid to the serotype antigens of the lipopolysaccharide nature with a view to their epidemiological evaluation.