TY - JOUR
T1 - Social environment and steroid hormones affect species and sex differences in immune function among voles
AU - Klein, Sabra L.
AU - Hairston, Joyce E.
AU - Devries, A. Courtney
AU - Nelson, Randy J.
N1 - Funding Information:
The authors thank Dr. Theresa Lee and Kerry Michele at the University of Michigan and Dr. Luci Roberts at the National Zoological Park in Washington, DC, for providing experimental meadow voles and meadow voles with which to start a breeding colony. We also thank Dr. Margaret Schadler at Union College, New York, for generously providing pine voles, and Dr. Kim Sawrey at the University of North Carolina, Wilmington, for the montane voles. We also thank Greg Demas, Lance Kriegsfeld, Chhaya Batra, Brooke Buckley, Serena Cardillo, Laura Katz, Violette Renard, Vinuta Rau, and Sue Yang for technical support. Finally, we thank George Bentley, Joseph Casto, Scott MacDougall-Shackelton, and Tom Hahn and his laboratory citizens for their helpful comments on early drafts of the manuscript. This research was supported by MH 57535 (formerly HD22201) and in part by NICHD P30 HD 06268 and NSF grant IBN 97-23420.
PY - 1997/8
Y1 - 1997/8
N2 - Testosterone has bipotential effects on male fitness; that is, it both suppresses immune function and maintains characteristics important for reproductive success. Presumably, these effects of testosterone may be more pronounced among polygynous species because testosterone concentrations are generally higher among polygynous than monogamous males. The present study examined sex and species differences in cell-mediated immunity among four arvicoline rodents. The role of mating system and sex steroids in sex differences in immune function was examined in individually housed polygynous meadow (Microtus pennsylvanicus) and montane (M. montanus) voles and monogamous prairie (M. ochrogaster) and pine (M. pinetorum) voles in Experiment 1. No sex differences in splenocyte proliferation were observed among the four species and circulating testosterone concentrations did not correlate with immune function of individuals within each species. The contribution of social isolation to these results was examined in Experiment 2, in which meadow and prairie voles were housed individually, or with same- or opposite-sex conspecifics in either pairs or groups of four per cage for 28 days. Overall, prairie voles exhibited more robust immune responses than meadow voles when housed in pairs or in same-sex groups. Sex differences in immune function were also apparent; male meadow voles had higher immune responses than female conspecifics when housed in pairs, whereas female prairie voles had higher responses than male conspecifics when housed in same-sex pairs. Circulating sex steroid hormones and corticosterone appear to mediate some, but not all, of the changes in immune function evoked by differential housing conditions. Taken together, these results suggest that social factors have significant effects on immunity and should be considered in studies of sex differences in immunity at both proximate and ultimate levels.
AB - Testosterone has bipotential effects on male fitness; that is, it both suppresses immune function and maintains characteristics important for reproductive success. Presumably, these effects of testosterone may be more pronounced among polygynous species because testosterone concentrations are generally higher among polygynous than monogamous males. The present study examined sex and species differences in cell-mediated immunity among four arvicoline rodents. The role of mating system and sex steroids in sex differences in immune function was examined in individually housed polygynous meadow (Microtus pennsylvanicus) and montane (M. montanus) voles and monogamous prairie (M. ochrogaster) and pine (M. pinetorum) voles in Experiment 1. No sex differences in splenocyte proliferation were observed among the four species and circulating testosterone concentrations did not correlate with immune function of individuals within each species. The contribution of social isolation to these results was examined in Experiment 2, in which meadow and prairie voles were housed individually, or with same- or opposite-sex conspecifics in either pairs or groups of four per cage for 28 days. Overall, prairie voles exhibited more robust immune responses than meadow voles when housed in pairs or in same-sex groups. Sex differences in immune function were also apparent; male meadow voles had higher immune responses than female conspecifics when housed in pairs, whereas female prairie voles had higher responses than male conspecifics when housed in same-sex pairs. Circulating sex steroid hormones and corticosterone appear to mediate some, but not all, of the changes in immune function evoked by differential housing conditions. Taken together, these results suggest that social factors have significant effects on immunity and should be considered in studies of sex differences in immunity at both proximate and ultimate levels.
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U2 - 10.1006/hbeh.1997.1402
DO - 10.1006/hbeh.1997.1402
M3 - Article
C2 - 9344689
AN - SCOPUS:0031208809
SN - 0018-506X
VL - 32
SP - 30
EP - 39
JO - Hormones and Behavior
JF - Hormones and Behavior
IS - 1
ER -