Summary
Effective immune responses require antigen uptake by antigen‐presenting cells (APC), followed by controlled endocytic proteolysis resulting in the generation of antigen‐derived peptide fragments that associate with intracellular MHC class II molecules. The resultant peptide–MHC class II complexes then move to the APC surface where they activate CD4+ T cells. Dendritic cells (DC), macrophages and B cells act as efficient APC. In many settings, including the T helper type 1 (Th1) ‐dependent, proteoglycan‐induced arthritis model of rheumatoid arthritis, accumulating evidence demonstrates that antigen presentation by B cells is required for optimal CD4+ T cell activation. The reasons behind this however, remain unclear. In this study we have compared the activation of CD4+ T cells specific for the proteoglycan aggrecan following antigen presentation by DC, macrophages and B cells. We show that aggrecan‐specific B cells are equally efficient APC as DC and macrophages and use similar intracellular antigen‐processing pathways. Importantly, we also show that antigen presentation by aggrecan‐specific B cells to TCR transgenic CD4+ T cells results in enhanced CD4+ T cell interferon‐γ production and Th1 effector sub‐set differentiation compared with that seen with DC. We conclude that preferential CD4+ Th1 differentiation may define the requirement for B cell APC function in both proteoglycan‐induced arthritis and rheumatoid arthritis.
A multifaceted cooperative research program involving industry, government and universities was initiated to determine the effects of feeding lactating dairy cows rations containing various levels of cotton‐seed and cottonseed meal that had been naturally contaminated with aflatoxins. Evidence is presented that ammoniation of aflatoxin‐contaminated cottonseed and cottonseed meal eliminates the aflatoxins, producing a product safe for feeding to ruminants. The aflatoxin M1 content of milk samples of individual cows receiving rations containing (a) prime cottonseed meal, (b) aflatoxin contaminated meal, and (c) aflatoxin contaminated meal that had ammoniation treatment is reported. Data comparing results with (d) prime cottonseed, (e) aflatoxin contaminated seed, and (f) aflatoxin‐contaminated seed that had ammoniation treatment are also reported. None of the milk samples from cows fed ammoniated rations contained any detectable M1 by the modified Jacobson et al. methodology used. The sensitibity of the method in this laboratory is 0.1 μg M1/liter of milk. Under the conditions of this study, aflatoxin M1 levels are related to the levels of aflatoxin B1 consumed in the diet of the cows. Conversion ratios are reported. Aflatoxin M1 levels in the milk, relative to the time of the cows’ initial ingestion of aflatoxin B1, the persistence of M1 in the milk after discontinuing ingestion of B1, and disappearance of M1 under the conditions of the analytical methodology used relative to storage time and temperatures, are reported for liquid milk and for frozen milk. Milk containing the highest level of aflatoxin M1 was treated with rennet. An 80:20 partion of aflatoxin M1 was observed between curd and whey, respectively.
subjects with 1, 2 and 3 positive samples during a 24 hour period were 52%, 14% and 14% respectively in IPF patients and 20%, 12% and 4% in control subjects. There was no significant difference in reflux-related quality of life or respiratory quality of life between pepsin positive and pepsin negative patients measured using the REFLUX questionnaire (mean 93.6 ± 2.6 SEM vs 97.8 ± 2.3, p = 0.47) and SGRQ (49.5 ± 3.5 vs 34 ± 11.9, p = 0.1). The HARQ score was significantly higher in pepsin positive patients (23.8 ± 3.3 vs 7.5 ± 3.3, p = 0.03). Conclusion Salivary pepsin measurement is simple, convenient and acceptable to patients. Our results confirm an increased prevalence of positive salivary pepsin in IPF patients compared to healthy volunteers but demonstrate a marked temporal variability. Therefore, more than one sample or repeated sample collection is required for optimal sensitivity.
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