Relationship between an 85 kDa Protein and the Protective Effects of Mycoplasma pneumoniae

Abstract

In the immunoblot analysis, sera from patients infected with Mycoplasma pneumoniae reacted with the 168 kDa (P1) and the 85 kDa proteins of virulent strain FH-P24 and P24-S1 mutant strain but not with the 85 kDa protein of P24-S11. Sera of hamsters and BALB/c mice, which had been immunized with live vaccines, were tested. In FH-P24 immunized animals, 100% or 80%, and in P24-S1, 40% of hamsters and 60% of BALB/c mice, developed antibodies against the 85 kDa protein, but antibodies were not detected in sera of P24-S11 immunized animals. The correlation between the development of antibodies to 85 kDa protein in the sera of vaccinated animals and the effects of protection by living vaccines were suggested.Mycoplasma pneumoniae is a major cause of epidemic nonviral pneumonia in children and young adults. An effective vaccine against M. pneumoniae disease would therefore be desirable.There have been three basic approaches to vaccine development, a whole-cell formalin-inactivated vaccine (22,23,25), a live attenuated vaccine (4, 11, 12) and a purified component vaccine (3,5,6). A single dose of inactivated vaccine has only a minimal protective effect. Multiple doses of vaccine containing adjuvant protect hamsters. The protective effect of inactivated vaccine was dose-dependent (1). Live vaccines composed of M. pneumoniae strains attenuated by continuous passages in vitro or temperature-sensitive mutants protected hamsters, but are unsuitable for human use because they retained partial virulence or decreased immunogenicity (4, 12). A current approach to vaccine development is based on producing cell extract vaccines made of defined cell components of the pathogen (5-7), especially the disease-related and virulence-related antigenic components, such as the attachment protein P1 (17, 18). It is not clear whether a vaccine made entirely of the P1 protein would be effective in protection against M. pneumoniae disease.We previously isolated nonhemolysis mutants of M. pneumoniae FH-P24 by the nitrosoguanidine (NTG) method (31, 32). Two of those mutants, P24-S1 and P24-S11, lost the virulence to golden hamsters. Only P24-S1 live vaccine showed protectivity in hamsters and BALB/c mice (33, 34) . The antibody, especially of 455

Mycoplasma pneumoniaeand Its Role as a Human Pathogen

“…Development of live attenuated vaccines administered intranasally or by aerosol inhalation in animal models showed some protective efficacy against disease upon rechallenge with virulent strains, suggesting that stimulation of local mucosal defense mechanisms is important (123,135,449). Development of a serum antibody response after mucosal immunization may or may not occur, depending on the immunogen (123,135,450). Unfortunately, the live attenuated vaccines never made it to human use due to concern over residual virulence of the vaccine strain of M. pneumoniae.…”

“…While the importance of the P1 adhesin in mediating M. pneumoniae cytadherence and initiation of disease cannot be denied, animal studies using P1 as a vaccine antigen have not demonstrated protective efficacy (76,(204)(205)(206). Experimental animal studies involving mice (449,450) hamsters (18,(75)(76)(77), guinea pigs (206), and chimpanzees (21,153) have continued through the 1980s and 1990s, but to our knowledge there have been no recent clinical trials in humans with any newer versions of M. pneumoniae vaccines, and there is no indication that any type of vaccine will be approved for use against M. pneumoniae any time soon.…”

A spontaneous hemadsorption-negative mutant of Mycoplasma pneumoniae exhibits a truncated adhesin-related 30-kilodalton protein and lacks the cytadherence-accessory protein HMW1

“…We have considerable evidence that the two proteins B and C are identical with the cleavage fragments of the open reading frame 6 (ORF6) gene product (40-and 90-kDa proteins) of the P1 operon, which consists of three ORFs in the order ORF4, ORF5 (P1), ORF6 (11,17,19,21,22,26,27,35,43). Biochemical and immunological studies revealed the location of the ORF6 gene product at the tip-like organelle of M. pneumoniae in close proximity to the P1 protein (11,26,27).…”

“…Characterization of spontaneously cytadherence-negative mutants (9,21,22) or comparable mutants obtained after nitrosoguanidine treatment (12,13,43) resulted in the identification of proteins which are necessary for effective adherence to host cells. In addition to the adhesin P1 (170 kDa) and the adhesin-related 30-kDa protein (3,4,7,10,15,16,18,40), which are not sufficient for M. pneumoniae cytadherence, three membrane proteins of 85, 72, and 37 kDa (designated B, A, and C, respectively, by Hansen et al [12]) and five proteinaceous components (HMW1 to -5) of the cytoskeleton-like triton shell are involved in the attachment process (17,24,30,(35)(36)(37)(38)43). These proteins are generally designated accessory proteins.…”

“…In addition to the adhesin P1 (170 kDa) and the adhesin-related 30-kDa protein (3,4,7,10,15,16,18,40), which are not sufficient for M. pneumoniae cytadherence, three membrane proteins of 85, 72, and 37 kDa (designated B, A, and C, respectively, by Hansen et al [12]) and five proteinaceous components (HMW1 to -5) of the cytoskeleton-like triton shell are involved in the attachment process (17,24,30,(35)(36)(37)(38)43). These proteins are generally designated accessory proteins.We have considerable evidence that the two proteins B and C are identical with the cleavage fragments of the open reading frame 6 (ORF6) gene product (40-and 90-kDa proteins) of the P1 operon, which consists of three ORFs in the order ORF4, ORF5 (P1), ORF6 (11,17,19,21,22,26,27,35,43). Biochemical and immunological studies revealed the location of the ORF6 gene product at the tip-like organelle of M. pneumoniae in close proximity to the P1 protein (11,26,27).…”