STUDIES ON NOCARDIA AND OTHER ACTINOMYCETALES .2. ANTIGENIC RELATIONSHIPS SHOWN BY SLIDE AGGLUTINATION TESTS

Abstract

The antigenic behavior of a collection of strains including numerous representatives of Nocardia, Mycobacterium, and 2 species of Strepto-myces was examined by means of slide-agglutination tests with antiserum prepared in rabbits. When members of the Nocardia asteroides, N. brasiliensis, N. corallina, and N. opaca groups were compared, they were found to behave in a generally similar manner. Strains of a given species sometimes showed antigenic homogeneity, but frequently significant cross reactivity with antiserum was exhibited to other strains and species within these groups. The members of these groups exhibited various degrees of cross reactivity with antimycobacterial serum, but were only very rarely, if at all, affected by antiserum vs. Streptomyces or the "streptomyces-like" Nocardia. The "streptomyces -like" Nocardia, and the two species of Streptomyces tested exhibited greater evidence of antigenic individuality although some cross reactions were observed. These strains showed little, if any, reactivity with the fragmenting Nocardia or Mycobacterium species. Mycobacteria such as Mycobacterium fortuitum, M. phlei, M. smegmatis, and M. tuberculosis, while manifesting distinctive serologic properties, did sometimes react significantly with antiserum vs. fragmenting Nocardia but not with antiserum vs. "streptomyces-like" Nocardia or Streptomyces species. Aside from evidence of the distinctiveness and/or cross reactivity of strains and species within the respective groups, the results of the study have emphasized anew the relative lack of relationships, demonstrable also by other means, between the genera Nocardia and Mycobacterium, on the one hand, and Streptomyces (including here the so-called "streptomyces-like" Nocardia), on the other.