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Full-Text Articles in Animal Sciences

Major Histocompatibility Complex Class I- And Ii-Deficient Knock-Out Mice Are Resistant To Primary But Susceptible To Secondary Eimeria Papillata Infections, Marco L. Schito, Bill Chobotar, John R. Barta May 1998

Major Histocompatibility Complex Class I- And Ii-Deficient Knock-Out Mice Are Resistant To Primary But Susceptible To Secondary Eimeria Papillata Infections, Marco L. Schito, Bill Chobotar, John R. Barta

Faculty Publications

Two distinct mechanisms seem to function in reducing oocyst output during Eimeria papillata infections in mice. For naive mice, immunity was afforded by a T-cell-independent gamma-interferon (IFN-γ) response mediated by natural killer (NK) cells. On reinfection, resistance was associated with T-cells and, to a lesser extent, perforin. To determine if antigen presentation with major histocompatibility complex (MHC) molecules was required to control oocyst production by NK cells during primary infection or by T-cells during secondary infection, mutant mice that lacked H2-IAβb (Aβb(-/-)) or β2-microglobulin (β2m(-/-)) were used. Since MHC molecules are required for the maturation of αβ T-cells, Aβb(-/-) and …


Supernumerary Teeth In Pleistocene, Recent, And Hybrid Individuals Of The Spermophilus Richardsonii Complex (Sciuridae), H. Thomas Goodwin Jan 1998

Supernumerary Teeth In Pleistocene, Recent, And Hybrid Individuals Of The Spermophilus Richardsonii Complex (Sciuridae), H. Thomas Goodwin

Faculty Publications

A supernumerary distal upper molar, always expressed bilaterally, occurred in Pleistocene (one of 204) and Recent (five of 1,667) specimens of the Spermophilus richardsonii complex. Among Recent specimens with the abnormality, three of four with known provenance came from adjacent colonies with hybrids of S. richardsonii (Richardson's ground squirrel) and S. elegans (Wyoming ground squirrel). Elsewhere, the trait was rare in S. richardsonii (one of 947) and absent in S. elegans (out of 668). Affected individuals exhibited normal P3-M2, but two aberrant teeth distal to M2. Aberrant teeth exhibited a mosaic of features typical of M2, M3, and atypical of …