Susceptibility of three strains of conventional adult mice to intestinal colonization by an isolate of Escherichia coli 0157:H7

NRC publication: Ye

Surface-exposed epitopes on the major outer-membrane protein of Chlamydia trachomatis defined with peptide antisera

The surface exposure of computer-predicted, linear B-cell epitopes on the major outer-membrane protein (MOMP) of Chlamydia trachomatis serovar B was assessed using antibodies raised against synthetic peptides in conjunction with immunogold transmission electron microscopy. Several of the chosen peptides elicited antibodies which reacted with both denatured and native MOMP. The majority of the exposed epitopes were found within the variable segments of MOMP. For each of the epitopes identified, the extent of their surface accessibility varied both among individual organisms and different developmental forms. Evidence for two distinct subspecies-specific epitopes within VS4 is presented

Ação do napsilato de propoxifeno durante a prenhez da rata albina (Rattus norvegicus albinus, Rodentia, Mammalia): ensaio biológico

Utilizamos 50 ratas prenhes que foram divididas em cinco grupos de dez. Todas as ratas receberam diariamente, por gavagem 1 ml de solucao, desde o zero ate o 20º dia de prenhez. O grupo I foi considerado controle, recebeu agua destilada. As ratas do grupo II, assim como os grupos restantes receberam solucao de acacia a 5% em solucao aquosa, associado ou nao ao napsilato de propoxifeno. As ratas do grupo III receberam 5 mg/kg de peso de napsilato de propoxifeno. O quarto grupo 15 mg/kg por dia e o quinto grupo 45 mg/kg por dia de napsilato de propoxifeno. Os pesos maternos foram considerados no inicio e ao 7º, 14ºe 20º dia da prenhez. No 20º dia, as matrizes foram sacrificadas. Nossos resultados mostraram que a solucao de acacia e o napsilato de propoxifeno em altas dosagens interferiu no ganho de peso materno, embora estas diferencas nao tenham sido significantes. Com relacao ao peso individual dos fetos, das ninhadas e das placentas, observou-se maior ganho de peso no grupo controle quando comparado ao grupo que recebeu 45 mg/kg de peso de napsilato de propoxifeno. Quanto as reabsorcoes, numero de fetos, numero de implantacoes e o numero de placentas nossos resultados que as doses de napsilato de propoxifeno administradas nao alteraram essas variaveisBV UNIFESP: Teses e dissertaçõe

The major outer membrane protein of Chlamydia trachomatis: critical binding site and conformation determine the specificity of antibody binding to viable chlamydiae

The major outer membrane protein (MOMP) is the prime candidate for the development of a chlamydial vaccine. Antibodies to the subspecies-specific epitope neutralize chlamydial infection. Monoclonal antibodies (MAbs) to this epitope were prepared either by immunization with whole chlamydiae or with a 16 amino acid synthetic peptide. The critical binding site on the subspecies epitope for these MAbs was determined to single amino acid resolution using several hundred solid-phase peptides. A frame shift of just one amino acid in critical binding site completely prevented antibody binding to viable chlamydiae. A single MAb to whole organisms was capable of spanning both the surface-exposed, conformation-dependent, subspecies epitope and a buried, conformation-independent species epitope some 10 A distant. Immunization with peptide generated an MAb with reduced binding constraints which permitted the antibody to bind with broadened species-specificity at the subspecies binding site. The results show for the first time the importance of both critical binding site and conformation at the subspecies epitope. We suggest that the conformational flexibility of short, epitopic peptide vaccines may in some cases be advantageous, giving rise to extended specificity not attained with the natural protein

Chlamydia trachomatis major outer membrane protein epitopes expressed as fusions with LamB in an attenuated aroA strain of Salmonella typhimurium; their application as potential immunogens

The major outer-membrane protein (MOMP) of Chlamydia trachomatis is the focus of attention for chlamydial vaccine design, particularly those serovar- and subspecies-specific epitopes which provoke neutralizing immune responses. Selected surface-exposed B-cell epitopes of MOMP, incorporating B-subspecies specificities, were expressed as fusions with LamB, an inducible outer-membrane transport protein of Escherichia coli. These recombinant chlamydial-LamB proteins were correctly transported to the outer membrane of both E. coli and an aro A mutant of Salmonella typhimurium. The immunogenicity of the constructs was investigated in a mouse model of chlamydial salpingitis. After oral immunization, recombinant S. typhimurium were recovered from the livers of mice for up to two weeks, and a serum IgG response was induced both to the Salmonella and to the inserted chlamydial epitopes. By contrast, intravenous inoculation was ineffective. Although these LamB fusions proved only weakly immunogenic, this approach should be useful for investigating the ability of attenuated S. typhimurium vaccines incorporating chlamydial epitopes to stimulate protective mucosal immunity in the mouse model of chlamydial salpingitis

Archaeosomes as self-adjuvanting delivery vehicles for acellular vaccines against intracellular bacteria

Peer reviewed: YesNRC publication: Ye

The major outer-membrane proteins of Chlamydia trachomatis serovars A and B: intra-serovar amino acid changes do not alter specificities of serovar- and C subspecies-reactive antibody-binding domains

The major outer-membrane protein (MOMP) of Chlamydia trachomatis is a promising candidate antigen for chlamydial vaccine development. We have sequenced the MOMP genes for a serovar A and a serovar B isolate and have compared these new sequences with those already reported. Intra-serovar changes in the inferred amino acid sequences of the surface-exposed variable segments known to be responsible for binding of neutralizing antibody were observed. Nevertheless, epitope mapping with solid-phase peptides showed that these intra-serovar changes did not affect the binding of serovar- and subspecies-specific, potentially protective antibodies. Variable segment 1 of C. trachomatis serovar A contained two adjacent antibody-binding sites, one of which was C-subspecies specific while the other was serovar A specific. Therefore the subspecies binding site for C-complex organisms is in variable segment 1, whilst that for B-complex organisms is in variable segment 4. This work shows that MOMP sequences are relatively stable within the serovar categorization for isolates taken decades apart from different continents. Within a given serovar, however, limited interchange of functionally related amino acids may occur without impairing the binding of serovar-specific antibody