In this study the effects of repeated antigen injections on total complement (C') and C'4 of guinea pig serum were investigated to determine if constant antigenic stimulation would show changes in the C' and C'4 titers. Attempts were also made to correlate any changes with variations in antibody titers during the repeated antigen injections.

This work attempts to establish some phenomenon of a rise in titer of C'3 and C'4 due to antigenic stimulation. Normal level of complement is established and compared to other workers as well as against guinea pig levels. Young rats were bled to establish normal levels of complement. The animals were then injected with an antigenic substance and after a period of seven days were bled again to determine the level of complement. Various antigenic and non-antigenic substances were used as well as normal saline injections for control.

The principal purpose of this work was to determine the effect of immunized guinea pig serum upon the survival time of tumor infected mice, and to make a correlation between this effect and the complement titer.

Orientadores: Renata de Oliveira Mattos Graner, Flávia Sammartino Mariano Rodrigues / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-26T11:30:42Z (GMT). No. of bitstreams: 1 Oliveira_ThaisRossinide_M.pdf: 1438459 bytes, checksum: a127a667898930e41649ac3faebb8d1a (MD5) Previous issue date: 2014 / Resumo: Streptococcus sanguinis é uma espécie pioneira comensal das superfícies dos dentes, que também está envolvida na endocardite infecciosa. Sua alta prevalência na cavidade oral indica capacidade de adaptar-se e sobreviver a diversos fatores de defesa presentes nesse nicho. Para se adaptar ao ambiente e a fatores do hospedeiro, as bactérias utilizam-se de sistemas reguladores de transcrição de dois componentes (SDC), que modulam a regulação de genes em respostas a diferentes estímulos. Neste estudo avaliou-se o papel do SDC VicRK e CovR, na susceptibilidade de S. sanguinis a opsonização pelo sistema complemento. Para isso, foram analisados os níveis de deposição de C3b / iC3b na presença de soro em um total de sete cepas clínicas de S. sanguinis, e as frequências de fagocitose por polimorfonucleares (PMNs) do sangue humano foram comparados entre as cepas S. sanguinis SK36 e mutantes knockout de vicK (SKvic) e covR (SKcov), genes estes que codificam componentes VicK e CovR, respectivamente. A cepa de S. mutans U159 foi utilizada como referência. Resumidamente, as cepas foram incubadas com soro humano a 2 ou 20% por 30 min (37 ° C, 10% de CO2), lavadas, e a presença de C3b associada à superfície foi detectado utilizando anticorpos anti-C3b humano (conjugado com FITC), sendo quantificadas por citometria de fluxo. Para avaliar as frequências de fagocitose por PMNs, as cepas foram incubadas com sangue humano durante tempos de 5, 15, 30 e 60 min (37 ° C, 10% de CO2), fixadas e coradas com Giemsa. PMNs com bactérias intracelulares, foram contados utilizando um microscópio de luz (1000 x) e os resultados expressos em relação a análise de um total de 200 PMNs. Resultados: As percentagens de deposição de C3b em SKvic, SKcov e SK36 foram de 11,3 (± 2,61), 40,2 (± 1,46) e 37,9% (± 3,97), respectivamente. Percentagem de superfície C3b foi significativamente menor em cepas de S. sanguinis em comparação a cepa de S.mutans (Kruskal Wallis, p <0,05), e em SKvic em comparação a cepa SK36 (Kruskal Wallis, p <0,05). As frequências médias de fagocitose por PMNs não foram afetadas, e foram 88, 99,3 e 99% em SKvic, SKcov e SK36, respectivamente. Conclusão: a inativação do VicK, mas não de CovR, reduz a deposição de C3b em S. sanguinis SK36. Cepas de S. sanguinis também são menos suscetíveis a deposição de C3b em comparação a S. mutans / Abstract: Streptococcus sanguinis is a commensal pioneer species of the tooth surfaces, which is also involved in infectious endocarditis. Its high prevalence in the oral cavity indicates ability to survive to several host defense factors present in the oral niches. To sense and respond to environmental and host factors, bacteria apply regulatory two-component systems (TCSs), which modulate gene transcription in response to different stimuli. This study evaluated the role of TCS VicRK and CovR in S. sanguinis susceptibility to opsonization by the complement system. To this aim, a total of seven S. sanguinis strains were analyzed, and levels of deposition of C3b/iC3b on the present of serum, and the frequencies of phagocytosis by polymorphonuclear (PMNs) in human blood were compared between parent S. sanguinis strain SK36 and knockout mutants of vicK (SKvic) and covR (SKcov) (genes encoding VicK and CovR components, respectively). S. mutans strain U159 was used as reference. Briefly, strains were incubated with 2 or 20% of human serum during 30 min (37°C, 10%CO2), washed, and the presence of surface-associated C3b was detected using anti-human C3b antibodies (FITC conjugated), which were quantified by flow cytometry. To assess the frequencies of phagocytosis by PMN, strains were incubated with human blood during 5, 15, 30 and 60 min (37°C, 10% CO2), fixed and stained with Giemsa. PMN with intracellular bacteria were counted using a light microscope (1000 x) and expressed in relation to a total of 200 PMN analyzed. Results: The percentages of C3b deposition on SKvic, SKcov and SK36 were 11.3 (± 2.61), 40.2 (± 1.46) and 37.9% (± 3.97), respectively. Percentage of surface C3b was significantly lower in S. sanguinis strains compared to S. mutans (Kruskal Wallis, p < 0.05), and in SKvic compared to SK36 (Kruskal Wallis, p < 0.05). The mean frequencies of phagocytosis by PMN was not affected, and were 88, 99.3 and 99% in SKvic, SKcov and SK36, respectively. Conclusion: the inactivation of the vicK, but not of covR, reduces the deposition of C3b in S. sanguinis SK36. S. sanguinis strains are also less susceptible to C3b deposition compared to S. mutans / Mestrado / Microbiologia e Imunologia / Mestra em Biologia Buco-Dental

Nonopsonic invasion of mononuclear phagocytes by Mycobacterium tuberculosis (M. tb.) is likely important in the establishment of a primary infection in the lung. M. tb. binds to a variety of phagocyte receptors, of which the mannose receptor and the complement receptor type 3 (CR3) may support nonopsonic binding. CR3, a β₂ integrin, is a target for diverse intracellular pathogens, but its role in nonopsonic binding remains uncertain. We have examined the binding of M. tb. to human CR3 heterologously expressed in Chinese hamster ovary (CHO) cells, thereby circumventing the problems of competing receptors and endogenously synthesised complement, which are inherent in studies with mononuclear phagocytes. The surface expression and functional activity of CR3 were confirmed by rosetting with beads coupled to anti-CR3 monoclonal antibodies (MAbs) and with C3bi-coated microspheres, respectively. We found thatM. tb. binds 4-7-fold more avidly to CR3- expressing CHO cells than to wild-type cells, and importantly, that this binding is very similar in the presence of fresh or heat-inactivated human or bovine sera, or no serum. The binding of M. tb. to the transfected CHO cells is CR3-specific, as it is inhibited by anti-CDllb and anti-CD18 MAbs; interestingly, binding is not inhibited by a MAb (2LPM19c) specific for the C3bi-binding site on CDI lb. Electron micrographs of infected CR3-expressing CHO cells reveal the presence of intracellular bacteria enclosed in well-defined, membrane-bound vacuoles. We conclude that the binding of M. tb. to CR3 is nonopsonic and that the organism likely expresses a ligand that directly binds to CR3.

The main efforts in this paper are directed towards the "crew complement" problem on American Airlines, and the solution found in the Tripartite Agreement. Included is an account of the major events in the airline industry that led to the present "crew complement" problem, and its existence on other airlines.

No description available.

Coiled-Coil Domain Containing 9 is a novel gene located beside C5aR1/R2 on murine chromosome 7. This proximal relationship is mirrored on human chromosome 19, making this research translational and relevant to the medical field. CCDC9-/- mice were created through a contract research organization utilizing CRISPR/Cas9 gene editing. Necropsy, gross examination, hematology, and clinical chemistry analysis were conducted to ensure that the global knockout of the CCDC9 gene did not induce any abnormalities in the development of the mice. Bone Marrow Derived Macrophages and Thioglycolate Elicited Peritoneal Macrophages were utilized from wild type and CCDC9-/- mice to explore the cytokine response from these macrophages when stimulated with various pattern recognition receptor agonists. Poly (I:C) and LPS were the two agonists that led to the most significant difference in cytokine release. Interactions with Poly (I:C), a synthetic double-stranded RNA that activates anti-viral RNA sensing immune responses, were targeted to elucidate how CCDC9 may be interacting with RNA. Meanwhile, interactions with LPS demonstrated that the role of CCDC9 is not specific to RNA-sensing but plays a modulatory role in the TLR4 and LPS pathway. These agonists were then paired with complement anaphylatoxin, C5a, and stimulated TEPM to explore the proximal relationship between CCDC9 and C5aR1/R2. The pairing with Poly (I:C) did not reveal any significant changes, but the pairing with LPS lead to a cytokine decrease that was not mirrored in CCDC9-/- macrophages. In-vivo applications were established in which wild type and CCDC9 -/- mice were injected intraperitoneally with LPS and Poly (I:C) to investigate the cytokine release. CCDC9-/- mice and cells consistently displayed a greater inflammatory cytokine induction when encountering stimulators of viral and bacterial pathogen sensing, suggesting that CCDC9 plays a role in immune function. / 2025-03-07T00:00:00Z

No description available.

No description available.