iNKT cells in allergic disease.

Recent studies indicate that invariant TCR+ CD1d-restricted natural killer T (iNKT) cells play an important role in regulating the development of asthma and allergy. iNKT cells can function to skew adaptive immunity toward Th2 responses, or can act directly as effector cells at mucosal surfaces in diseases such as ulcerative colitis and bronchial asthma. In mouse models of asthma, NKT cell-deficient strains fail to develop allergen-induced airway hyperreactivity (AHR), a cardinal feature of asthma, and NKT cells are found in the lungs of patients with chronic asthma, suggesting a critical role for NKT cells in the development of AHR. However, much work remains in characterizing iNKT cells and their function in asthma, and in understanding the relationship between the iNKT cells and conventional CD4+ T cells.

Adaptation at specific loci. VII. Natural selection, dispersal and the diversity of molecular-functional variation patterns among butterfly species complexes (Colias: Lepidoptera, Pieridae).

Natural genetic variants at the phosphoglucose isomerase, PGI, gene differ in spatial patterning of their polymorphism among species complexes of Colias butterflies in North America. In both lowland and alpine complexes, molecular-functional properties of the polymorphic genotypes can be used to predict genotype-specific adult flight performances and resulting large genotypic differences in adult fitness components. In the lowland species complex, there is striking uniformity of PGI polymorph frequencies at a number of sites across the American West; this fits with earlier findings of strong, similar differences in fitness components over this range. In an alpine complex, Colias meadii shows similar uniformity of PGI frequencies within habitat types, either montane steppe or alpine tundra, over several hundred kilometres in the absence of dispersal. At the same time, large shifts (10-20%) in frequency of the most common alleles occur between steppe and tundra populations, whether these are isolated or, as in some cases, are in contact and exchange many dispersing adults each generation. Data on male mating success of common C. meadii PGI genotypes in steppe and tundra show heterozygote advantage in both habitat types, with shifts in relative homozygote disadvantage between habitats which are consistent with observed frequency differences. Nonadaptive explanations for this situation are rejected, and alternative, thermal-ecology-based adaptive hypotheses are proposed for later experimental test. These findings show that strong local selection may dominate dispersal as an evolutionary agent, whether or not dispersal is present, and that selection may often be the major force promoting 'cohesion' of species over long distances. This case offers new opportunities for integrating studies of molecular structure and function with ecological aspects of natural selection in the wild, both within and among species.

An attempt to establish an inbred line of mice genetically resistant to Cowdria ruminantium.

An attempt to establish an inbred line of mice resistant to Cowdria ruminantium failed. First generation couples were constituted from those mice out of 100 males and 100 females that had survived infection with the Kümm stock of C. ruminantium and that were serologically negative to the indirect fluorescent antibody test. An attempt to establish 10 separate inbred lines by constituting next generation brother and sister matings from predominantly seronegative survivor mice from the preceding generation, was unsuccessful because too few mice survived the challenge. The percentage seronegative survivors increased to 94% over the first 6 generations, but then declined sharply during the next.

Genetic aspects of the hormonal regulation of some testis enzymes during pubertal development of the rat.

Using a rat model, it was shown that the synthesis of certain testis enzymes during pubertal development is under hormonal control, which acts as regulatory mechanism for gene expression during eukaryotic differentiation. Esterase activity and its electrophoretic banding pattern can be specifically induced by human chorionic gonadotrophin (HCG). Alcohol dehydrogenase and 3beta-hydroxysteroid dehydrogenase are independently induced by HCG, and are apparently coded for by 2 different genetic cistrons.