Species-specific monoclonal antibody to a 43,000-molecular-weight membrane protein of Mycoplasma pneumoniae

Immunoblot analyses of chimpanzee sera after infection and after immunization and challenge with Mycoplasma pneumoniae

Consecutive weekly or biweekly serum specimens obtained during a 3- or 4-month study from 16 chimpanzees were examined by immunoblot analyses to identify the immunogenic components of Mycoplasma pneumoniae. Six experimentally infected chimpanzees showed significant signs of overt disease, including cough, pharyngitis, rhinitis, fever, and loss of appetite. The sera of these infected chimpanzees recognized from 17 to 20 protein bands. Two control chimpanzees that were not inoculated were included in the study. Three chimpanzees immunized with a formalin-inactivated OSU-1A vaccine and three chimpanzees immunized with an experimental acellular vaccine showed minimal signs of disease on challenge. After challenge, the serum immunoblot responses of the immunized chimpanzees were similar to those of the infected chimpanzees. Before challenge, the sera of two previously infected chimpanzees recognized protein bands of 169 (which comigrated with the P1 adhesin), 148, 130, 117, 86, 61, 44, 35, 30, and 29 kDa. After challenge, the previously infected chimpanzees showed the most intense serum immunoblot responses and were most protected against colonization and disease. The sera from each of the 16 chimpanzees examined recognized a large number of immunogenic components, and the serum immunoblot responses were virtually identical to those of patients. Sera from each chimpanzee and patient recognized 169-, 148-, 130-, 117-, 86-, 44-, and 35-kDa bands and many of them recognized 67-, 63-, 61-, 56-, 32-, 30-, and 29-kDa protein bands.

Evidence for a common epitope on the surface of Mycoplasma gallisepticum defined by monoclonal antibody

An antigen containing a common epitope in most strains of Mycoplasma gallisepticum was purified by isoelectric focusing and used in the production of monoclonal antibodies (mAb). Of several mAb produced, only one mAb reacted with focused component and with all six strains of M. gallisepticum except strain 6/85. This mAb was designated MG3D6.A5, and it was subsequently purified with immobilized rProtein Atm. The MG3D6.A5 mAb recognized a common epitope on a molecule with relative molecular weight of 98 kilodaltons (kDa), termed p98. No binding was observed when the MG3D6.A5 mAb was reacted against antigens extracted from other mycoplasma species, indicating its species-specificity. Physicochemical studies revealed that p98 had an isoelectric point of 5.2, was stable to heat, and was resistant to periodate oxidation but sensitive to trypsin treatment, suggesting that p98 is a nonglycosylated protein. Furthermore, ultrastructural studies with colloidal gold revealed that M. gallisepticum cells were selectively stained with MG3D6.A5 mAb to p98. The latter was focally distributed on the surface of a mycoplasma cell membrane near the attachment organelle. These results suggest that p98 is a highly conserved protein in M. gallisepticum strains, is immunogenic, and is surface-accessible; its binding specificity to MG3D6.A5 mAb could be used to identify M. gallisepticum in multiple cultures.

The simultaneous direct detection of Mycoplasma pneumoniae and Legionella pneumophila antigens in sputum specimens by a monoclonal antibody immunoblot assay

An immunoblot (Western) assay was developed employing a species-specific monoclonal antibody to a 43 kDa Mycoplasma pneumoniae membrane polypeptide and a species-specific monoclonal antibody to 29 kDa Legionella pneumophila outer membrane protein. This assay could simultaneously detect these two different antigens directly in sputum. The 43 kDa M. pneumoniae antigen was detected by this assay in each of three M. pneumoniae culture-confirmed sputum specimens. In addition, the 29 kDa L. pneumophila antigen was detected in three of three L. pneumophila culture-confirmed sputum specimens. Neither of these two specific antigens were detected in induced sputum specimens from ten normal individuals.

Immunological cross-reactivity of a Mycoplasma pneumoniae membrane-associated protein antigen with Mycoplasma genitalium and Acholeplasma laidlawii

A murine monoclonal antibody, OC2F5, reacts with a Mycoplasma pneumoniae antigen with an approximate Mr of 43,000. This antigen is trypsin and proteinase K sensitive and partitions in the detergent phase of a Triton X-114 solution. The monoclonal antibody cross-reacts with an antigen from both Mycoplasma genitalium and Acholeplasma laidlawii with a similar molecular weight. This cross-reactivity should be considered in the development of M. pneumoniae antigen detection systems based on the use of antibodies directed to this protein antigen.