Significance of Antibody to Mycoplasma as Measured by Metabolic‐inhibition Techniques

Abstract

A problem central to the study of mycoplasma has been the classification of strains and the identification of isolates from clinical material. Several serologic approaches to the identification of mycoplasma have been employed by laboratories in recent years. These approaches have permitted the recognition of new species of mycoplasma which were indistinguishable from established species in biologic properties.Recently we developed a new serologic technique which can be used for identification of mycoplasrna and for serodiagnosis and seroepidemiology. It is based upon Jensen's observation that specific antiserum inhibited the reduction of tetrazoliurn by Mycoplasma pneumoniae in broth medium.' We modified Jensen's method by incorporating substrates such as glucose, arginine, or urea in the medium as indicators of mycoplasma growth.-In this manner, antibody for all of the human mycoplasma species and many of the animal strains can now be measured by metabolic-inhibition (MI) techniques.Metabolic-inhibition Techniques. Strains of "classical" mycoplasma can be divided into two groups on the basis of whether or not they produce acid from carbohydrates. Acid production causes an acid shift in the pH of the medium. Almost all of the non-acid-producing strains metabolize the amino acid arginine with the release of ammonia into the medium and a concomitant alkaline shift in the pH. Acid or alkaline pH shift can be visualized by the incorporation of phenol red in the medium. In our tests, Haflick's medium6 supplemented with glucose was adjusted initially to pH 7.8, whereas medium supplemented with arginine was adjusted to pH 7.0. Specific antiserum inhibited metabolism of the mycoplasma and prevented an acid or alkaline shift in pH. The highest dilution of antiserum which prevented pH change (color change) was considered 8s the MI antibody end point. For maximum sensitivity, it was necessary to record the MI antibody titer when controls containing mycoplasma but not antiserum had changed approximately 0.5 pH unit, The MI titer of immune serum was not related to the size of the mycoplasma inoculum if the titer was recorded when

Antigenic differences within the speciesMycoplasma hominis

“…Serological differences between strains were noted by Nicol & Edward (1953) in agglutination tests and by Purcell et al (1967) in metabolic inhibition tests. Taylor-Robinson, Ludwig et al (1965) demonstrated differences between two strains in indirect haemagglutination tests with human sera, but not with hyperimmune rabbit sera.…”

“…The resulting mean titres were then analysed according to Alling (1967) and Purcell et al (1967) When the antigens are identical, therefore, R = 1 and logb R = 0, whereas when they are completely unrelated, R = 0 and logbR = -oo. Thus, the more logbR deviates from 0, the greater the differences between the strains.…”

“…Since intraspecies differences between strains of M. hominis have been demonstrated by several serological techniques (Nicol & Edward, 1953;Taylor-Robinson, Ludwig et al 1965;Purcell et al 1967), the membrane and soluble fractions of three strains of M. hominis were compared by immunodiffusion to see if any differences could be detected between the antigens of the three. The strains were also compared by MI, IHA and CF, and the results analysed statistically to determine the degree of relatedness.…”

The Isolation and Comparative Biological and Physical Characteristics of T-mycoplasmas of Cattle

“…For this reason, it is difficult to prepare antigens for the production of antisera in rabbits. Consequently, serological work is difficult, although possible by the metabolic inhibition-technique (Purcell et al 1966;Purcell et al 1967;Ford, 1967), and will be reported later. fig.…”

Serological Comparison of Bovine T-mycoplasmas

“…Most studies on the serology of human T-mycoplasmas have been made with the metabolism inhibition test (Purcell, Taylor-Robinson, Wong & Chanock, 1966) and these have demonstrated the serological diversity of this group of micro-organisms (Purcell et al 1967). N o correlation between serotype and anatomical site of colonization, or serotype and isolation from pathological conditions or normal subjects, has been found (Ford, 1967;Purcell, Chanock & Taylor-Robinson, I 969).…”