Bovine viral diarrhea virus (BVDV) has long been associated with a wide variety of clinical syndromes and immune dysregulation, many which result in secondary bacterial infections. Current understanding of immune cell interactions that result in activation and tolerance are explored in light of BVDV infection including: depletion of lymphocytes, effects on neutrophils, natural killer cells, and the role of receptors and cytokines. In addition, we review some new information on the effect of BVDV on immune development in the fetal liver, the role of resident macrophages, and greater implications for persistent infection.

Dietary probiotics supplementation exerts beneficial health effects. Since cigarette smoking reduces natural killer (NK) activity, we evaluated the effect of Lactobacillus casei Shirota (LcS) intake on NK cytotoxic activity in male smokers. The double-blind, placebo-controlled, randomised study was conducted on seventy-two healthy Italian blue-collar male smokers randomly divided for daily intake of LcS powder or placebo. Before and after 3 weeks of intake, peripheral blood mononuclear cells were isolated and NK activity and CD16+ cells' number were assessed. Daily LcS intake for 3 weeks significantly increased NK activity (P < 0·001). The increase in NK activity was paralleled by an increase in CD16+ cells (P < 0·001). Before intake, NK cytotoxic activity inversely correlated with the number of cigarettes smoked (R − 0·064). LcS intake prevented the smoke-dependent expected NK activity reduction. The analysis of the distribution of changes in smoke-adjusted NK activity demonstrated that the positive variations were significantly associated with LcS intake, while the negative variations were associated with placebo intake (median value of distributions of differences, 20·98 lytic unit (LU)/107 cells for LcS v. − 4·38 LU/107 cells for placebo, P = 0·039). In conclusion, 3 weeks of daily LcS intake in Italian male smokers was associated with a higher increase in cytotoxic activity and CD16+ cells' number in comparison to the placebo intake group.

Quercetin, a flavonoid found in fruits and vegetables, is a strong antioxidant with anti-inflammatory, antimicrobial and immune-modulating properties. The purpose of the present study was to investigate the effects of long-term quercetin supplementation on innate immune function and inflammation in human subjects. Female subjects (n 120; aged 30–79 years) were recruited from the community and randomised to one of three groups, with supplements administered using double-blinded procedures: 500 mg quercetin/d (n 38), 1000 mg quercetin/d (n 40) or placebo (n 42). Subjects ingested two soft chew supplements twice daily during the 12-week study period. Fasting blood samples were obtained pre- and post-study and were analysed for plasma quercetin, IL-6, TNF-α and leucocyte subset cell counts. Natural killer cell activity (NKCA) and lymphocyte subsets were assessed in a subset of seventy-four subjects. Granulocyte oxidative burst activity (GOBA) and phagocytosis were assessed in sixty-four subjects. Eighteen subjects had overlapping data. Quercetin supplementation at two doses compared with placebo increased plasma quercetin (interaction effect; P < 0·001) but had no significant influence on blood leucocyte subsets, plasma IL-6 or TNF-α concentration, NKCA, GOBA or phagocytosis. NKCA was inversely correlated with BMI (r − 0·25; P = 0·035) and body fat percentage (r − 0·38; P = 0·001), and positively correlated with self-reported physical fitness level (r 0·24; P = 0·032). In summary, results from the present double-blinded, placebo-controlled, randomised trial indicated that quercetin supplementation at 500 and 1000 mg/d for 12 weeks significantly increased plasma quercetin levels but had no influence on measures of innate immune function or inflammation in community-dwelling adult females.

The immunological relationship beween the mammalian fetus and its mother during pregnancy has been considered similar to that between a transplanted allograft and its recipient ever since Medawar (1953) first proposed the concept of the ‘fetus as an allograft’ in the early 1950s. Based on this analogy, it has been assumed that implantation of the fetal placenta in the uterus would be controlled similarly by a maternal immune response mediated by T-cells recognizing paternally-derived alloantigens expressed by the placenta. Surprisingly, recent evidence suggests that implantation might involve predominantly a novel allogeneic recognition system based on natural killer cells rather than T-cells (Loke & King, 1995). The cellular and molecular basis of this local immune interaction between the fetal placenta and maternal uterus is now the focus of intense research interest. Since aberrant implantation can cause a variety of clinical problems, including miscarriage, intrauterine growth retardation and pre-eclampsia, an understanding of the immunological mechanism by which this process is controlled could lead to the development of regimens to improve fetal growth and development.

We present a case report of an aggressive natural killer T cell lymphoma in a police officer who presented with combined features of orbital cellulitis and mid-facial destruction. However, his initial diagnosis was confused with other disease conditions that had overlapping features. This emphasizes the significance of clinical alertness and adequate tissue sampling; this can have a great impact on early diagnosis and treatment.

Injection trials with compatible and non-compatible Onchocerca species into S. damnosum s.l., the vector of human and bovine onchocerciasis, demonstrated that the rapid killing of microfilariae within the blackfly's haemocoel is species specific. In the presence of the peptide RGDS as a blocking agent for integrin-like receptors of haemocytes, the survival of O. ochengi microfilariae in its natural intermediate host was significantly increased. This increased survival 24 h p.i. correlated with a significant decrease of apoptosis levels in the microfilariae following a 2 h exposure to the haemolymph in vivo. These findings suggest that haemocytes are directly involved in the killing of Onchocerca microfilariae in the blackfly.