Biomedical subjects

C C Soberg

Publications and source records attributed to C C Soberg.

5 recordsLinked to original sources

PubMed1999

Severe injury triggers antigen-specific T-helper cell dysfunction.

Although it is established that post-injury immune dysfunction involves alterations in T-cell function, the effects of injury on T-cell function in vivo are poorly understood. This study uses a mouse injury model and an antigen immunization approach to investigate the influence of injury on antigen-specific T-helper cell function. We report here that injury triggered a significant reduction in antigen-specific T-helper-1 (Th1)-dependent IgG2a antibody formation, while IgM, IgG1, and IgE production was unchanged. In addition, injury caused a reduction in cytokine production (IL-2, IFNgamma and IL-10) by antigen-stimulated T-cells. We also demonstrate that interleukin 12 (IL-12), a cytokine that promotes Th1 cell differentiation, restored IgG2a antibody formation and corrected the injury-induced reduction in antigen-stimulated cytokine production. Taken together, these findings indicate that severe injury induces a dramatic reduction in Th1 cell function in vivo and suggest that therapies designed to restore Th1 cell function may be beneficial to the injured host.

Animals↗

PubMed1999

Injury primes the immune system for an enhanced and lethal T-cell response against bacterial superantigen.

We previously reported the high lethality of CD4+ T-cell activation in burn-injured T-cell receptor (TCR) transgenic mice. This suggested to us that T-cells may play a role in the development of the systemic inflammatory response syndrome (SIRS) which can occur after severe injury. In this study, we sought a more clinically relevant model to test the hypothesis that naturally produced bacterial toxins that are known to act as potent polyclonal T-cell activating agents may induce a similar lethal shock-like response in injured, non-TCR transgenic mice. Accordingly, sham- or burn-injured mice were treated with various doses of staphylococcal enterotoxin A (SEA), then observed for 48-hour mortality. We observed 94% and 56% 48-h mortality when burn-injured mice were given 15 microg and 10 microg of SEA, respectively, while neither SEA dose caused mortality in sham-injured mice. The assessment of serum cytokine levels demonstrated significantly elevated interleukin 2 (IL-2) and tumor necrosis factor alpha (TNFalpha) levels when compared to sham mice (P < 0.01). In vitro studies confirmed our in vivo results and also demonstrated elevated levels of interferon gamma (IFNgamma) (P < 0.01). We also observed a novel injury-dependent switch from CD4+ to CD8+ T-cells as the dominant T-cell type producing TNFalpha and IFNgamma in response to SEA stimulation in vitro. Taken together, our findings indicate that injury primes the immune system for an augmented early T-cell response that can result in a lethal shock-like syndrome.

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PubMed1999

Interleukin 10 is not essential for survival or for modulating T-cell function after injury.

BACKGROUND: Interleukin 10 (IL-10) is thought to be protective in injury and sepsis. However, we recently reported that IL-10 antagonism can be beneficial after burn injury. This study used IL-10-deficient (IL-10 [-/-]) mice to further define the role of IL-10 after injury. METHODS: Wild-type (WT) C57BL/6 or IL-10 (-/-) mice were anesthetized, sham or burn injured, and immunized subcutaneously with a T-cell-dependent protein antigen. Ten days later antigen-specific serum antibody isotype formation was measured by enzyme-linked immunosorbent assay. In addition, antigen-stimulated splenic T-cell proliferation and cytokine production (interleukin 2, interferon gamma, and tumor necrosis factor-alpha) were measured. RESULTS: Burn-injured IL-10 (-/-) mice survival (80%) was equivalent to that of burn-injured WT mice (74%). An injury-dependent loss of T-helper 1 (Th1)-type antibody isotype (IgG2a) formation occurred in both WT and IL-10 (-/-) mice. In vitro studies indicated that burn injury caused reduced antigen-stimulated splenic T-cell proliferation and Th1-type (interleukin 2 and interferon gamma) cytokine production in WT and IL-10 (-/-) mice, whereas burn-injured IL-10 (-/-) mice produced high levels of antigen-stimulated tumor necrosis factor-alpha. CONCLUSIONS: IL-10 is not essential for survival after burn injury or for several injury-induced changes in adaptive immune function, including Th1-type antibody isotype formation, T-cell proliferation, and Th1-type cytokine production.

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PubMed1998

Burn injury primes naive CD4+ T cells for an augmented T-helper 1 response.

BACKGROUND: The mechanisms responsible for altered T-cell responses and cytokine production after injury are not well understood. We used T-cell receptor (TCR) transgenic mice to study burn injury effects on naive versus antigen-activated CD4+ T cells in vivo. METHODS: One week after sham or burn injury, lymph node cells were prepared from TCR transgenic mice and stimulated with TCR transgene-specific antigens. T-cell proliferation was measured and culture supernatants were tested for interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, and IL-10 by enzyme-linked immunosorbent assay (ELISA). Burn injury effects on antigen-activated T cells were studied by immunizing TCR transgenic or wild-type mice at the time of injury. RESULTS: The antigen-stimulated proliferation of native CD4+ T cells was unaffected by burn injury and no increase in T-helper 2 (Th2)-type cytokine production was observed. Instead, burn injury augmented INF-gamma production by naive CD4+ transgenic T cells, and IL-2 production was marginally reduced. Thus, burn injury primed native T cells for an enhanced Th1-type response. In contrast, antigen-specific proliferation, IL-2, and IFN-gamma production by T cells harvested from immunized wild-type mice were suppressed. Unexpectedly, high mortality was observed when burn-injured TCR transgenic mice were immunized. CONCLUSION: Our results show that burn injury has differential effects on naive and antigen-activated CD4+ T cells and can prime naive CD4+ T cells.

Animals↗

PubMed1997

Anti-interleukin-10 antibody restores burn-induced defects in T-cell function.

BACKGROUND: Studies have shown that susceptibility to sepsis after severe injury correlated with reduced production of T-helper 1 (Th1) cytokines (interleukin-2 [IL-2] and interferon-gamma [IFN-gamma]) and a persistence of T-helper 2 (Th2) cytokines (IL-4 and IL-10). The mechanisms responsible for this effect are not clear. We used a T-dependent antigen to study both the effect of burn injury on antigen-specific Th functions in vivo and the effect of anti-IL-10 antibody on these functions. METHODS: Male A/J mice were anesthetized and given a 25% scald burn or a sham burn. On day 0 all mice were immunized with 100 micrograms trinitrobenzene sulfonic acid (TNP) haptenated ovalbumin (TNP-OVA) in complete Freund's adjuvant. Mice (10 per group) were given 250 micrograms monoclonal rat antimurine IL-10 antibody (anti-IL-10 MAB) or control rat immunoglobin G (IgG) on day 0 and 100 micrograms anti-IL-10 MAB or IgG on day 2. On day 10 the mice were killed to obtain serum and spleen cells. TNP-specific serum antibody isotype titers were determined by enzyme-linked immunosorbent assay (ELISA). Splenocyte proliferation and cytokine-production in response to TNP-OVA or to anti-CD3 MAB were determined by tritiated thymidine incorporation and by ELISA, respectively. RESULTS: Burn injury resulted in depressed levels of the TNP-specific IgG2a antibody isotype (Th1 dependent), whereas TNP-specific IgG1 and IgE (Th2 dependent) levels were not decreased in burn versus sham burn mice. Anti-IL-10 MAB but not IgG restored the IgG2a response. Burn injury also resulted in reduced TNP-OVA-specific proliferation of splenocytes, whereas anti-CD3 proliferation was equivalent in burn and sham mice. TNP-OVA-specific IL-2 and IFN-gamma production were significantly reduced by burn injury. Anti-IL-10 MAB restored TNP-OVA-specific proliferation and antigen-specific IL-2 and interferon-gamma production by splenocytes from burn mice. CONCLUSIONS: Burn injury induces the loss of antigen-specific Th1 cell function, and IL-10 acts as a trigger to down-regulate Th1 activity after injury.

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