A study of F38-type and related mycoplasmas by mycoplasmaemia and cross-immunization tests in mice

Abstract

SummaryIn vivomethods were used to study the F38-type mycoplasma in parallel with related mycoplasmas.Three of five strains of ‘bovine serogroup 7’ with an unknown history of subculture produced mycoplasmaemia in mice inoculated intraperitoneally. A strain of ‘bovine serogroup L’ also produced mycoplasmaemia, but no evidence of similar ability could be found for single strains ofMycoplasma capricolum, M. equigenitaliumandM. primatum, or for two strains of the F38-type mycoplasma.In cross-immunization tests a bovine serogroup 7 strain (NCTC 10133) and a strain (‘Blenheim’) of the SC (small colony) type ofM. mycoidessubsp.mycoideswere used for the purpose of challenge. Cross-protection was described as ‘complete’ or ‘partial’, depending on whether it was as great as, or less than, that produced by homologous vaccine. Although strain NCTC 10133 protected strongly, possibly completely, against Blenheim, and Blenheim gave partial protection against NCTC 10133, challenge with NCTC 10133 and Blenheim gave strikingly different results. Thus (1) F38-type strains,M equigenitaliumandM. primatumall gave partial cross-protection against NCTC 10133 but not against Blenheim, (2) NCTC 10133, unlike Blenheim, was seldom susceptible to partial cross-protection by LC (large colony) strains ofM. mycoidessubsp.mycoides, and (3) three SC strains – which would have protected completely against Blenheim – protected only partially against NCTC 10133. NCTC 10133 and Blenheim were similar, however, in thatM. capricolumandM. mycoidessubsp.caprifailed to cross-protect against them both.