Protection against Nippostrongylus brasiliensis infection in mice is independent of GM-CSF.

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a cytokine with the capacity to promote inflammation in a wide variety of infectious and inflammatory diseases. These conditions include allergic airway inflammation, which is driven by T-helper 2 (Th2) cells. Because of the importance of Th2 cells in parasite infections, we have investigated the role of GM-CSF in mice infected with the nematode Nippostrongylus brasiliensis. The effect of primary and secondary infection was investigated in mice lacking functional genes for GM-CSF (CSF2 genes) (ΔGM-CSF mice), and in mice lacking the cytokine receptor common ß chain (Δß mice), the latter being unable to signal in response to GM-CSF and interleukin (IL)-5. ΔGM-CSF mice showed no significant defect in parasite immunity, measured by larval numbers in the lungs, worm numbers in the intestine or egg numbers in the faeces, in either primary or secondary infection. By contrast, the Δß mice showed increased parasite burden, with higher numbers of lung larvae after secondary infection and higher numbers of intestinal worms and faecal eggs after both primary and secondary infection. Unexpectedly, there were increased numbers of circulating eosinophils in the ΔGM-CSF mice, associated with significantly reduced larval numbers in the lungs. These results indicate that GM-CSF is redundant in protection against N. brasiliensis infection, and that the increased susceptibility of Δß mice to infection is likely to be attributed to the lack of IL-5 signalling in these mice. The results suggest that clinical use of agents that neutralise GM-CSF may not be associated with increased risk of parasite infection.

Political rhetoric, immigration attitudes, and contemporary prejudice: a Mexican American dilemma.

The authors examined political candidates' social stereotypes of Mexican immigrants in mainstream media accounts. From those popular themes, they formed semantic differential scales, which they administered to participants (N = 201) with 1 of 4 scenarios describing an illegal immigrant: of Mexican vs. English Canadian descent and with vs. without several parking tickets. Consistent with contemporary theories of prejudice (J. F. Dovidio & S. L. Gaertner, 1996), the participants indicated the greatest agreement with the pejorative themes when the immigrant described was of Mexican descent and had accumulated parking tickets. Psychologically, the parking tickets served as a nonethnic rationale for discriminating against that ethnic group. The authors discuss the social and public policy implications of Mexican immigration as a political phenomenon.