Immunology. A state of the art lecture

Effects of environmental stress and gender on associations among symptoms of depression and the serotonin transporter gene linked polymorphic region (5-HTTLPR)

The short (s) variant of the serotonin transporter (5-HTT) gene linked functional polymorphic region (5-HTTLPR) is associated with depression. Stressful life events, gender, and race have been shown to moderate this association. We examined the relationship between 5-HTTLPR genotype and symptoms of depression in two samples. Study 1 = 288 participants from a study of caregiver stress; and Study 2 = 142 participants from a study examining psychosocial stressors, genetics, and health. Main effects of 5-HTTLPR on symptoms of depression were examined, along with moderation by stress (caregiving status or low childhood socioeconomic status (SES), gender, and race. The 5-HTTLPR x stress group x gender interaction was significant in both samples (P < 0.003, and P < 0.008, respectively). For females, the s allele, combined with caregiving stress (Study 1) or low childhood SES (Study 2), was associated with higher depression scores as compared to participants in the non-stressor group and those with the long (l) allele; whereas, in males, the l allele, combined with a stressor, was associated with higher depression scores as compared to those in the non-stressor group and those with the s allele. Findings from two independent samples suggest that the association of 5-HTTLPR with depression varies according to gender and stressful life events.

A critical analysis of multiple chemical sensitivities

Multiple chemical sensitivities (MCS) is a chronic condition of irritation and inflammation of sensory organs, gastrointestinal distress, fatigue, and compromised neurological function, including learning and memory deficits, unpleasant smells, tingling of nerves, and sensory discomfort. Victims report these symptoms after exposure to unfamiliar chemicals. Some studies have linked MCS to immune system dysregulation. MCS is believed to be a disease that spreads between various target organs, and is caused by sensitization to chemicals with very different structures. MCS is often attributed to free radical production and stress, which indirectly cause spreading because of damage to the immune system.

Effects of in vitro corticosterone on chicken T- and B-lymphocyte proliferation

1. The effects of corticosterone and the time of its addition to cultures, on concanavalin A (Con-A) and pokeweed mitogen (PWM)-induced lymphocyte proliferation were studied. 2. Peripheral blood lymphocytes (PBL) were isolated from Cornell K-strain Single Comb White Leghorn immature male chickens and cultured with various concentrations of Con-A or PWM. Corticosterone, in different concentrations, was added to the cultures either 2 h before or 2 h after the addition of the respective mitogen. 3. Addition of corticosterone 2 h before the mitogens caused a significant suppression of lymphocyte proliferation in response to both Con-A and PWM stimulation. Also addition of corticosterone 2 h after the mitogens caused significant suppression of proliferation in response to both mitogens; however, the degree of suppression was not as great. 4. The results indicate that after early activation events are initiated by the mitogens, lymphocytes are less sensitive to the effects of corticosterone. Because less suppression was seen in the cultures preincubated with PWM than those with Con-A, it is likely that there are different sensitivities to corticosterone in the cell populations that respond to these mitogens.

Effects of human recombinant interleukins on stimulation-evoked noradrenaline overflow from the rat perfused spleen

Experiments were carried out in the isolated spleen of the rat to study in a lymphoid organ the influence of interleukins (ILs) on noradrenaline release. Spleens were perfused with Tyrode's solution and the overflow of endogenous noradrenaline was determined by HPLC with electrochemical detection. Perivascular electrical stimulation (4 or 10 Hz, 20-28 mA, 2 min) caused an increase in noradrenaline overflow and in perfusion pressure, both of which were markedly reduced by perfusion with Ca(2+)-free solution, abolished by tetrodotoxin, unaffected by hexamethonium, and subject to alpha 2-adrenoceptor- and muscarinic receptor-mediated modulation as shown by the effects of rauwolscine and methacholine. Human recombinant IL-1 beta and IL-2 and mouse recombinant IL-2 10 ng/ml failed to affect the evoked overflow of noradrenaline after an exposure time of 15 min. In contrast, human recombinant IL-1 beta and IL-2 0.1 ng/ml reduced the evoked overflow after exposure for 80 min; the inhibition tended to increase 30 min later despite washout. Murine recombinant IL-2 1.2 ng/ml caused no change after contact with the tissue for 80 min but there was an inhibition 30 min later after washout. Human recombinant IL-6 (0.1 ng/ml) caused no significant change. The inhibitory effect of low concentrations of IL-1 beta and IL-2 supports the idea that locally produced mediators of the immune system may affect neuronal function.