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The putative R1 protein of Streptococcus agalactiae as serotype marker and target of protective antibodies
Author(s) -
MOYO SYLVESTER R.,
MAELAND JOHAN A.,
LYNG RANDI V.
Publication year - 2001
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1034/j.1600-0463.2001.091206.x
Subject(s) - serotype , streptococcus agalactiae , antibody , antiserum , myeloma protein , microbiology and biotechnology , antigen , biology , subtyping , streptococcus , strain (injury) , virology , bacteria , immunology , computer science , programming language , anatomy , genetics
The streptococcal R1 protein was studied by means of anti‐R1 antibodies prepared by appropriate cross‐absorption of rabbit antiserum raised against the group B streptococcal (GBS) strain ATCC 12403 (D136C), serotype III/R1. The protein was a ladder‐forming antigen according to banding patterns in immunoblotting, similar to several other GBS proteins, and was susceptible to digestion by both pepsin and trypsin. Antibody‐based testing revealed that 10% of Norwegian GBS isolates expressed the R1 protein, most frequently capsular antigen type V strains (72%) and less frequently type III strains (3%). None of 132 GBS strains from Zimbabwe, including 39 type V strains, expressed the R1 protein. R1‐specific rabbit antibodies showed protective activity in mice challenged with a GBS type V/R1 strain. The results show that the R1 protein is an important GBS serotype marker in strains from certain geographical areas, notably for the subtyping of capsular type V strains, and that this protein is a target of protective antibodies.