Microbiology and immunology
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Microbiol. Immunol. · Nov 2009
Protective effects of affinity-purified antibody and truncated vaccines against Pseudomonas aeruginosa V-antigen in neutropenic mice.
Virulent P. aeruginosa strains express PcrV, one of the translocational components of the type III secretion system. PcrV has been reported to be a protective antigen against lethal P. aeruginosa infection. The PcrV region, which contributes to protective immunity against P. aeruginosa infection, was investigated by using genetically engineered, truncated PcrV proteins and affinity-purified anti-PcrV antibodies against the truncated PcrV proteins. ⋯ In the case of passive immunization, administration of affinity-purified anti-PcrV IgG against either PcrV1-294 or PcrV139-258 showed significantly higher efficacy against lethal P. aeruginosa infection than did original anti-PcrV IgG and Mab166. The increased efficacy of affinity-purified anti-PcrV IgG implies that more potent anti-PcrV strategies are possible. The results of this study are crucial to the development of an effective PcrV vaccine for active immunization and to an appropriate blocking anti-PcrV antibody against P. aeruginosa infection in humans.
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Microbiol. Immunol. · Oct 2009
Comparative StudyA novel DNA vaccine containing multiple TB-specific epitopes cast in a natural structure elicits enhanced Th1 immunity compared with BCG.
Vaccination is expected to make a major contribution to the goal of eliminating tuberculosis worldwide by 2050. Because the protection afforded by the currently available tuberculosis vaccine, BCG, is insufficient, new vaccine strategies are urgently needed. Protective immunity against MTB depends on generation of a Th1-type cellular immune response characterized by secretion of IFN-gamma from antigen-specific T cells. ⋯ After being immunized with DNA vaccine three times, all mice injected with ECANS had specific cellular immune responses. In addition, lymphocytes obtained from the spleen of ECANS immunized mice at week eight exhibited significantly greater specific lymphocyte proliferation, IFN-gamma secretion and CTL activity than those of mice that had been immunized with BCG. DNA vaccine with ECANS can successfully induce enhanced specific cellular immune response to PPD, and further study of its protective effects against Mycobacterium tuberculosis in vivo is needed.
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Microbiol. Immunol. · Jan 2009
IL-4-dependent induction of IgE basophils in peripheral blood and IgE B cells in spleen as respective indicators of allergen sensitization and a precursor of cells secreting allergen-specific IgE antibody.
It was recently reported by us that either primary i.n. or i.p. injection of cedar pollen extract into BALB/c mice, or a second s.c. injection of the allergen into i.v. or s.c. sensitized mice, causes an IL-4-dependent increase in total IgE serum antibody to produce allergen-specific IgE antibody upon further s.c. sensitization. To determine the biology of total IgE antibody, in the present study IgE+ cells in peripheral blood or lymphoid tissues of allergen-sensitized BALB/c mice have been characterized. In peripheral blood, mice sensitized one to three times with the allergen produced a 2.5- to 4-fold increase in the number of IgE+ cells, with a time-course similar to that of the concentration of total IgE antibody in serum. ⋯ On the other hand, the number of IgE+ cells in the lymphoid tissues did not change significantly after an i.n., i.p., i.v. or s.c. injection of allergen into the mice, whereas a second s.c. injection of the allergen into the i.v.-, but not into the i.n.-, i.p.- or s.c.-, sensitized mice induced a small number of IgE+/IgM+/B220+ B cells in the spleen. In contrast, IgE+ cells were not seen in the blood or spleen of IL-4 -/- mice after sensitization with the allergen. These results suggest that IgE+ basophils in the peripheral blood, and IgE+ B cells in the spleen, might be IL-4-dependently induced as an indicator of sensitization with allergen, and a precursor of cells secreting allergen-specific IgE antibody, respectively.
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Microbiol. Immunol. · Jan 2007
Antibiotics protect against septic shock in mice administered beta-glucan and indomethacin.
We have developed an animal model of sepsis in mice by repeatedly administering beta-glucan, a biological response modifier, and indomethacin (IND), a nonsteroidal anti-inflammatory drug. The combination of these drugs induced bacteremia by translocation of the enterobacterial flora, resulting in increasing the number of activated leukocytes, and inducing hyper cytokinemia. ⋯ However, the efficacy of antibiotics treatment was limited in mice administered IND orally. These findings strongly suggested that the antibiotics controlled the gut-associated action of IND and reduced various symptoms accompanying sepsis.
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Microbiol. Immunol. · Jan 2007
Occurrence of RD9 region and 500 bp fragment among clinical isolates of Mycobacterium tuberculosis and Mycobacterium bovis.
The present investigation dealt with the identification of Mycobacterium tuberculosis and M. bovis by RD9 region and 500 bp fragment PCR assays. Eight M. tuberculosis and 5 M. bovis characterized and identified from 40 human sputum and 41 bovine lung specimens and 20 M. tuberculosis and 9 M. bovis strains maintained at Mycobacteria Laboratory, Indian Veterinary Research Institute were included in this study. In this way, 28 M. tuberculosis and 14 M. bovis strains and, for comparison and control purpose, M. tuberculosis H37Rv, M. bovis BCG, M. canetti, M. smegmatis, M. phlei, M. chelonae, M. kansasii, M. xenopi and M. avium were subjected to RD9 and 500 bp amplification by PCR. ⋯ There was no amplification product of 500 bp found in M. canetti, M. smegmatis, M. phlei, M. chelonae, M. avium, M. kansasii, M. xenopi and was absent in all M. tuberculosis strains. The PCR assay results correlated 100% with the culture and biochemical results of the isolates. Our study suggested that PCR based on RD9 and 500 bp may effectively identify two closely related species of M. tuberculosis and M. bovis.