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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The polyclonal B cell activation (PBA) process induced by Klebsiella pneumoniae K34 (klebs) and Yersinia enterocolitica 03 (yers) was investigated. Both heat-inactivated bacteria and their cell wall biostructures (klebsM, muriene, protein I etc.) stimulate human blood B cells to differentiate into immunoglobulin-secreting cells without prior proliferation and without T cells. Klebs-activated B cells secrete mainly IgM and to a lesser degree IgG (mainly IgG2). The PBA process was regulated by CD4+ cells and monocytes, but not by CD8+ cells. While interleukin 2 is able both to induce proliferation and to enhance differentiation in klebs-activated B cell cultures, the low-molecular-weight B cell growth factor (BCGF) did not lead to a significant amount of 3H-thymidine uptake. In addition, in klebs-activated B cell cultures various anti-polynucleotide autoantibodies and the 16/6 idiotype were detectable. Thus, bacteria that induce nonsuppurative sequelae (e.g. klebs, yers) can use several mechanisms to overcome tolerance in their host.
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PMID:Polyclonal B-cell activation by bacteria that induce nonsuppurative sequelae. 257 82

Klebsiella pneumoniae K43 cell membrane preparations (Klebs M) have been characterized previously as a human polyclonal B cell activator (PBA) that stimulates purified B cells to differentiate into immunoglobulin (Ig) secreting cells with negligible prior or parallel proliferation and in the absence of T cells. The aim of the present study was to define the cellular interactions in the regulation of Klebs M induced B-cell differentiation. For this purpose OKT4+ and OKT8+ cell populations were negatively selected with reasonable purity by means of a panning technique or by complement-mediated cytolysis using monoclonal OKT4 and OKT8 antibodies. The resulting cell populations were added to purified autologous B cells exposed to Klebs M or, as a control, pokeweed mitogen (PWM). In the Klebs M system both the OKT4+ and the OKT8+ cell subsets markedly enhanced IgM production; however, the helper effect of the OKT4+ cell subset was much more intense than that of the OKT8+ subset. In the PWM system only the OKT4+ cells provided help for B-cell differentiation. The OKT8+ subset demonstrated suppressor activity in the presence of an adequate helper cell (OKT4+ subset) function. These results indicate that Klebs M behaves like a "relatively T cell-independent PBA".
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PMID:T-cell influence on the B-cell differentiation process induced by Klebsiella. 293 58

B-cell functions were investigated in a well-defined high-risk group for the development of AIDS/AIDS-related complex (ARC). Stimulation of mononuclear cells (MNC) with T-cell-independent polyclonal B-cell activators failed to increase high spontaneous IgG levels observed in vivo and in vitro. The secretion of IgM following stimulation with Klebsiella M (Klebs M) or Salmonella (Salm) membrane preparation increased by a factor of 4 to 6 and thus ranged between the results of the control group and those of AIDS/ARC patients; the response to a T-cell-independent B-cell mitogen, Staphylococcus aureus Cowan I (SAC), showed profound abnormalities as well in this group. This indicates that functional B-cell abnormalities can be seen in addition to T-cell dysfunctions in patients at increased risk for the development of AIDS/ARC.
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PMID:Abnormal B-cell response to T-cell-independent polyclonal B-cell activators in homosexuals presenting persistent generalized lymph node enlargement and HTLV-III antibodies. 301 48

The effect of the tumour-promoting agent TPA (12-0-tetra-dodecanoyl-phorbol-13-acetate) on the proliferation and Ig secretion response of blood and tonsil lymphocytes was investigated and compared to that of the T-cell-dependent polyclonal activators pokeweed mitogen (PWM) and group A streptococcal cell membranes (A-ScM) or the T-cell-independent B cell mitogen Staphylococcus aureus Cowan I (SAC) and a T-cell-independent B cell activator Klebsiella pneumoniae (Klebs M). In blood mononuclear cells (MNC), a rather weak, monocyte-dependent DNA synthetic response was observed after exposure to TPA, in comparison to PWM, A-ScM or SAC. Whereas highly purified B cells did not respond to TPA, purified T cells proliferated to a similar degree as unseparated MNC; moreover, the addition of T to B lymphocytes enhanced proliferation rates proportionally to the number of T cells added. This suggests that TPA acts as a polyclonal T cell activator (PTA) for human blood and tonsil cells. Similarly, TPA induced only small amounts of Ig secretion in blood and in tonsil MNC, as determined by an ELISA assay, and no significant Ig secretion in highly purified B cells. The rather weak B cell differentiation response was not due to a monocyte suppressor effect, since partially monocyte-depleted MNC or B cells responded similarly to the non-depleted cells. Thus, TPA cannot be considered as an alternative to other B cells stimulators, both with regard to DNA synthesis and Ig secretion.
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PMID:Influence of TPA (12-O-tetradodecanoyl-phorbol-13-acetate) on human B lymphocyte function. 387 51

Like "true" polyclonal B-cell activators (PBA) for murine B cells, crude membrane preparations of Klebsiella pneumoniae (Klebs M) and some other enterobacteriaceae stimulate human B cells to mature into immunoglobulin (Ig) secreting cells without significant prior proliferation and in the absence of T cells. To investigate the biochemically defined membrane component with this unique PBA property, we studied lipoprotein and murein isolated from E. coli, since other components (e.g., a variety of lipopolysaccharide (LPS) fragments) failed to imitate Klebs M as a PBA. Mononuclear cells (MNC) and B cell-enriched cell populations from healthy blood donors were stimulated with various doses of lipoprotein and murein and, in comparison, Klebs M and pokeweed mitogen (PWM). Cell cultures exposed to either lipoprotein, murein, or Klebs M failed to incorporate [3H]thymidine significantly after 5 days in culture. In contrast, there was significant DNA synthesis (stimulation index greater than 3) when PWM was given to the same MNC population. All stimulants, with the exception of lipoprotein, induced B-cell differentiation in MNC cultures, as measured by an ELISA quantitating secreted Ig in the culture supernatants. In cultures with B cell-enriched cell populations, however, only Klebs M and murein were able to induce the production of significant amounts of IgM. Thus, the actual PBA moiety contained in the crude membrane fraction (Klebs M) appears to be associated with murein. It is important to note that murein induced considerably weaker Ig secretion than Klebs M did.
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PMID:Human B-cell differentiation induced by murein. 389 24

ESI remain a major problem in patients undergoing peritoneal dialysis and are frequently the reason for catheter removal. The treatment is often costly and not effective and the need for routine prophylactics has to be clarified. In this study 38 peritoneal dialysis patients (15 F & 23 M, age: 18-73) were analysed prospectively for ESI and TI in respect to skin (exit site and inguinal area) and nostrils colonisation. There were 14 diabetics and 24 non-diabetics. All had standard double-cuff Tenckhoff catheter and none presented with ESI prior to the study. No treatment was applied on the basis of positive culture only. In 27 patients swab were repeated after 6-11 months. Eight episodes of ESI and three TI were recorded. Following pathogens were cultured: S.aureus in 4 Klebsiella pneumoniae in 2, Corynebacterium sp. in 1, negative in 1 and with TI S.aureus in 3. Positive nasal cultures (S.aureus, Klebs.pn.) were observed in 5 patients subsequently developing ESI (p < 0.01) and in 2 with TI. In 2 cases exit site was also colonized by pathogens responsible for ESI (p = NS). Inguinal area was colonized by various pathogens in 7 patients, but only one of these developed ESI (p = NS) and no one TI. There was no difference between diabetic and non-diabetics neither in the frequency of ESI, TI nor in nasal carriage of pathogens. In the majority of patients nostrils and inguinal area were colonized by S.epidermidis. When the second culture was analyzed it appeared that significantly more patients had exit site colonized by S.epidermidis (2 and 11 patients in 2 consecutive cultures respectively (p < 0.01). In conclusion, it appears that nasal carriers of pathogens like S.aureus and Klebsiella pneumoniae are more prone to ESI. Inguinal area and exit site colonization does not seem to precede ESI or TI. We would suggest that nasal carriage status should be routinely identified in all patients entering peritoneal dialysis programme and the carriers properly treated.
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PMID:[The effect of nasal and skin colonization on the development of exit site and peritoneal catheter tunnel infections in patients on peritoneal dialysis]. 1041 May 77