
serological relationships among human mycoplasmas as shown
by complement-fixation and gel diffusion
and robert m. chanock
antigenic relationships among human
mycoplasmas were studied by complement-
fixation and agar gel diffusion techniques.  four
recognized human species.  mycoplasma hominis
type 1, m. hominis type 2, m. salivarium, and
m. fermentans were antigenically distinct in
these tests.  in addition, m. pneumoniae (eaton
agent, the etiological agent of cold agglutinin-
positive atypical pneumonia) was different from
these four species.  although these species were
distinct, evidence of shared antigenic components
was obtained in complement-fixation and agar
gel diffusion tests.  since rabbits were immunized
with mycoplasmas grown in rabbit muscle infu-
sion broth supplemented with rabbit serum or,
in the case of m. pneumoniae, with infected chick
embryo lung suspension, the possibility that the
heterologous reactions resulted from antibody
to growth medium components could be excluded.
four recent mycoplasma isolates from the oro-
pharynx were analyzed, and three were shown to
be closely related to m. hominis type 1, and the
fourth was closely related to m. salivarium.
although the recent isolates could not be dis-
tinguished from the related "prototype" human
species by complement-fixation, differences could
be detected by the agar gel diffusion technique.
