transforming-growth-factor-beta and Dysentery--Bacillary

Volunteers were orally administered invasive, non-Shiga toxin-producing Shigella dysenteriae 1 to establish a challenge model to assess vaccine efficacy. In stepwise fashion, four separate groups were given 3 x 10(2), 7 x 10(3), 5 x 10(4), or 7 x 10(5) CFU. Using PBMC, proliferative responses and cytokine production were measured to S. dysenteriae whole-cell preparations and to purified recombinant invasion plasmid Ags (Ipa) C and IpaD. Anti-LPS and anti-Ipa Abs and Ab-secreting cells were also evaluated. Preinoculation PBMC produced considerable quantities of IL-10 and IFN-gamma, probably secreted by monocytes and NK cells, respectively, of the innate immune system. Following inoculation, PBMC from 95 and 87% of volunteers exhibited an increased production of IFN-gamma and IL-10, respectively, in response to Shigella Ags. These increases included responses to IpaC and IpaD among those volunteers receiving the lowest inoculum. No IL-4 or IL-5 responses were detected. Whereas there were no Ab or Ab-secreting cell responses in volunteers receiving the lowest inoculum, other dose groups had moderate to strong anti-LPS and anti-Ipa responses. These results suggest that in humans, type 1 responses play an important role in mucosal and systemic immunity to S. dysentariae 1.

Topics: Adhesins, Bacterial; Administration, Oral; Adolescent; Adult; Antibodies, Bacterial; Antibody-Producing Cells; Bacterial Proteins; Bacterial Toxins; Bacterial Vaccines; Colony Count, Microbial; Dose-Response Relationship, Immunologic; Dysentery, Bacillary; Gene Deletion; Humans; Interferon-gamma; Interleukin-10; Interleukin-12; Interleukin-15; Interleukin-2; Interleukin-4; Interleukin-5; Kinetics; Leukocytes, Mononuclear; Lymphocyte Activation; Shiga Toxins; Shigella dysenteriae; Transforming Growth Factor beta; Vaccines, Synthetic

In our study, infection with Shigella dysenteriae type 1 (n = 16) or Shigella flexneri in adults (n = 5) was associated with a gradual accumulation of mRNA for interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, IL-6, transforming growth factor-beta, IL-10, IL-4, TNF-beta, interferon (IFN)-gamma and perforin in the rectal biopsy samples during the convalescent stage of the disease demonstrated by in situ hybridization. In contrast, immunohistochemical staining in rectal tissues of cytokine protein-producing cells at the single-cell level exhibited a steady-state expression during 2-36 days after the onset of the disease. The frequency of cytokine mRNA-expressing cells varied in the range of 3-100-fold higher than that of the corresponding protein-synthesizing cells. The accumulation of cytokine mRNA in vivo during shigellosis represented a long-lasting phenomenon throughout the disease course, and may be linked to its immunopathogenesis. The results also indicate that assessment of both protein and mRNA in vivo may provide complementary information. Stimulation in vitro of peripheral blood mononuclear cells from normal healthy donors with Shigella-derived lipopolysaccharide or shiga toxin was carried out to elucidate the role of Shigella antigens in the regulation of translation of cytokine-specific mRNA. The incidence of cytokine (IFN-gamma, IL-6 and TNF-alpha) mRNA- and cytokine protein-expressing cells was very similar and congruent after both these Shigella-derived stimuli. We could, thus, not find evidence for shiga toxin-induced down-regulation of cytokine mRNA translation as the explanation for the observed discrepancy between cytokine mRNA and protein levels in the tissue biopsies.

Topics: Acute Disease; Adult; Cell Count; Convalescence; Cytokines; Dysentery, Bacillary; Gene Expression Regulation, Bacterial; Humans; Interleukins; Intestinal Mucosa; Lipopolysaccharides; Lymphotoxin-alpha; Membrane Glycoproteins; Perforin; Pore Forming Cytotoxic Proteins; Rectum; RNA, Messenger; Shigella dysenteriae; Shigella flexneri; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha