Increased levels of IgE and autoreactive, polyreactive IgG in wild rodents: implications for the hygiene hypothesis.
To probe the potential role of Th1 versus Th2 reactivity underlying the hygiene hypothesis, intrinsic levels of Th1-associated and Th2-associated antibodies in the serum of wild rodents were compared with that in various strains of laboratory rodents. Studies using rat lung antigens as a target indicated that wild rats have substantially greater levels of autoreactive, polyreactive immunoglobulin G (IgG), but not autoreactive, polyreactive IgM than do laboratory rats, both on a quantitative and qualitative basis. Increased levels of serum IgG and IgE were observed in both wild rats and wild mice relative to their laboratory-raised counterparts, with the effect being most pronounced for IgE levels. Further, wild rats had greater intrinsic levels of both Th1- and Th2-associated IgG subclasses than did lab rats. The habitat (wild versus laboratory raised) had a more substantial impact on immunoglobulin concentration than did age, strain or gender in the animals studied. The presence in wild rodents of increased intrinsic, presumably protective, non-pathogenic responses similar to both autoimmune (autoreactive IgG, Th1-associated) and allergic (IgE, Th2-associated) reactions as well as increased levels of Th1-associated and Th2-associated IgG subclasses points toward a generally increased stimulation of the immune system in these animals rather than a shift in the nature of the immunoreactivity. It is concluded that, at least to the extent that feedback inhibition is a controlling element of immunoreactivity, an overly hygienic environment may affect the threshold of both types of immune responses more so than the balance between the different responses.
Devalapalli
A P
AP
Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA.
Lesher
A
A
Shieh
K
K
Solow
J S
JS
Everett
M L
ML
Edala
A S
AS
Whitt
P
P
Long
R R
RR
Newton
N
N
Parker
W
W
D000818:Animals; D000830:Animals, Laboratory / Q000276:immunology*; D000835:Animals, Wild / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology; D015551:Autoimmunity / Q000276:immunology; D004777:Environment; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006920:Hygiene; D006967:Hypersensitivity / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D051381:Rats; D012377:Rodentia / Q000097:blood / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007073:Immunoglobulin E