Immune function studies splenocytes

One reasonably thorough study examined immune function in rats orally dosed at up to 400 mg/kg/day 2-butoxyethanol twice after immunization with trinitrophenyl-lipopolysaccharide (TNP-LPS) (Smialowicz et al 1992). Compared with controls, the 2-butoxyethanol had no adverse effect on antibody production, delayed B type hypersensitivity, natural killer cell function, or splenocyte production of cytokines. 

A single study in animals reported no effect in the splenic natural killer cell activity in rats orally exposed to 27.1 mg/kg/day 1,2-dimethylhydrazine (Locniskar et al. 1986). However, in mice injected with 75 mg/kg/day 1,1-dimethylhydrazine, a decreased T helper cell count was observed (Frazier et al. 1991). In vitro studies have reported that 1,1-dimethylhydrazine induces immunomodulation (enhancing some immune functions while diminishing others) in mouse lymphocytes and splenocytes (Bauer et al. 1990 Frazier et al. 1992). These data are limited, but suggest that humans exposed to hydrazines may be at risk of developing immunological effects. 

Recently, Sedqi et al. [24] were able to clone a delta opioid receptor complementary DNA by expression of cDNA library from activated thymocytes in Cos 7 cells, whose amino acid sequence was similar to the neural counterpart. Interestingly, they also observed that transcripts for kappa and mu opioid receptors were not detected in thymocytes. Furthermore, Gave-riaux et al. [25] demonstrated transcripts for the delta opioid receptor in T-lymphocyte, B-lymphocyte, and monocyte cell lines, as well as in murine splenocytes. However, they observed that the kappa opioid receptor transcript was only found in B-cell lines. These studies may suggest a selective expression of the delta opioid receptor in specific cells and tissues of the immune system and suggests specialized functions in different anatomical regions. 

The direct effects opioid and opioidlike peptides exhibit on cells of the immune system is both varied and, in some instances, contradictory, depending on which receptor subtype is being studied. Mu and kappa receptors generally affect immunofunction in a suppressive manner, where delta receptors tend to express immunostimulation [82-85]. However, selected delta antagonists have shown to elicit suppressive effects on B-cell proliferation, NK cell activity, and T-helper cell cytokine production [86]. The alteration of leukocyte function via opioid receptors will be discussed highlighting specific cell subtype immunomodulation. Endorphin shows a inhibitory effect on splenocyte proliferation through central and peripheral autocrine/paracrine pathways [87]. 

Following the observation that inadequate levels of methionine and choline during critical periods of embryonic development led to subclinical effects on the thymolymphatic system we examined the functional capacity of lymphocytes derived from these animals and their ability to react to SRBC immunization. Initial pilot studies with a limited number of animals showed a depressed response to the mitogen PHA in splenocytes from rats whose mothers were fed a marginal lipotrope diet during pregnancy (Newberne and Gebhardt,... 

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