IX. IDENTIFICATION OF MYCOPLASMAS
3 89
said to be less specific than GI. MI or immunofluorescence tests. On the
other hand, the CF test is useful at the intraspecies level, since it shows
more homogeneity between strains of the same species than the GI and
M I tests, which can apparently reflect small differences in the surface
antigens (Hollingdale and Lemcke, 1970; Forshaw and Fallon, 1972).
Thus in an identification procedure, C F may in some cases be useful in
confirming the relationship of an unknown to a recognised species when
other more specific tests have shown only a limited degree of crossreactivity. The sensitivity of the C F test is greater than that of GI and
double immunodiffusion tests, probably equal to that of direct agglutination
and immunofluorescence tests, but less than that of the M I test.
(g) Double immunodiffusion. Double immunodiffusion has been used quite
extensively in the classification of mycoplasmas (Taylor-Robinson et al.,
1964, 1965a; Lemcke, 1965, 1973; Kenny, 1969, 1972, 1973; Erne, and
Jurmanovl, 1973; Rosendal, 1974b). The sensitivity of this method is
much lower than that of MI, immunofluorescence or C F tests in that
antisera usually have to be used undiluted or at very low dilutions and high
concentrations of antigen are required. However, the method has the
advantage that reactions of individual determinants or antigens are observable. Other serological methods show the degree of cross-reactivity
between strains; immunodiffusion tests can indicate the basis of the
cross-reactions in terms of the number of determinants involved and the
relatedness of the cross-reacting components. Double immunodiffusion is
therefore unlikely to be used as a first step in identification, but rather to
investigate or substantiate relationships which have been suggested by GI,
M I or immunofluorescence tests. For example, the close relationship of a
group of equine mycoplasmas to M . felis that was suggested by G I and MI
tests was confirmed by immunodiffusion tests (Lemcke and Allam, 1974;
Allam and Lemcke, 1975).
I n regard to classification, analyses of the antigenic patterns of mycoplasmas by the double immunodiffusion test, or by the more sensitive
two-dimensional immunoelectrophoresis technique, have revealed the
existence of common antigens within groups of glycolytic Mycoplasma or
Acholeplasmn species (Kenny, 1969, 1972, 1973) as well as among arginineutilising Mycoplasma species (Taylor-Robinson et al., 1963 ; Lemcke,
196s; Fox et al., 1969; Kenny, 1972, 1973; Thirkill and Kenny, 1974). No
antigenic overlapping is, however, seen between these two biochemically distinct groups (Fox et al., 1969; Erne and Jurmanovri, 1973; Kenny,
1973).
Information about the presence or absence of antigenic relationships
between mycoplasma species found in a particular animal host may assist
3 89
said to be less specific than GI. MI or immunofluorescence tests. On the
other hand, the CF test is useful at the intraspecies level, since it shows
more homogeneity between strains of the same species than the GI and
M I tests, which can apparently reflect small differences in the surface
antigens (Hollingdale and Lemcke, 1970; Forshaw and Fallon, 1972).
Thus in an identification procedure, C F may in some cases be useful in
confirming the relationship of an unknown to a recognised species when
other more specific tests have shown only a limited degree of crossreactivity. The sensitivity of the C F test is greater than that of GI and
double immunodiffusion tests, probably equal to that of direct agglutination
and immunofluorescence tests, but less than that of the M I test.
(g) Double immunodiffusion. Double immunodiffusion has been used quite
extensively in the classification of mycoplasmas (Taylor-Robinson et al.,
1964, 1965a; Lemcke, 1965, 1973; Kenny, 1969, 1972, 1973; Erne, and
Jurmanovl, 1973; Rosendal, 1974b). The sensitivity of this method is
much lower than that of MI, immunofluorescence or C F tests in that
antisera usually have to be used undiluted or at very low dilutions and high
concentrations of antigen are required. However, the method has the
advantage that reactions of individual determinants or antigens are observable. Other serological methods show the degree of cross-reactivity
between strains; immunodiffusion tests can indicate the basis of the
cross-reactions in terms of the number of determinants involved and the
relatedness of the cross-reacting components. Double immunodiffusion is
therefore unlikely to be used as a first step in identification, but rather to
investigate or substantiate relationships which have been suggested by GI,
M I or immunofluorescence tests. For example, the close relationship of a
group of equine mycoplasmas to M . felis that was suggested by G I and MI
tests was confirmed by immunodiffusion tests (Lemcke and Allam, 1974;
Allam and Lemcke, 1975).
I n regard to classification, analyses of the antigenic patterns of mycoplasmas by the double immunodiffusion test, or by the more sensitive
two-dimensional immunoelectrophoresis technique, have revealed the
existence of common antigens within groups of glycolytic Mycoplasma or
Acholeplasmn species (Kenny, 1969, 1972, 1973) as well as among arginineutilising Mycoplasma species (Taylor-Robinson et al., 1963 ; Lemcke,
196s; Fox et al., 1969; Kenny, 1972, 1973; Thirkill and Kenny, 1974). No
antigenic overlapping is, however, seen between these two biochemically distinct groups (Fox et al., 1969; Erne and Jurmanovri, 1973; Kenny,
1973).
Information about the presence or absence of antigenic relationships
between mycoplasma species found in a particular animal host may assist