Table 1.

Occurrence of retinopathy in HLA-A29 transgenic mice

Mice	Age, months	Number of mice tested	Number of mice with retinopathy
A29-negative	≥12	25	0
A29-positive	4–15	31	12 (39%)
A29-positive	≤6	16	0
A29-positive	≥12	15	12 (80%)
A29M	≥12	6	4 (67%)
A29	≥12	9	8 (88%)

 Double transgenic mice (A29M) carrying human genes for the HLA-A29 heavy chain and β₂-microglobulin were crossed with B10 nontransgenic mice. Four types of offspring were obtained: single transgenic mice carrying only the transgene for the HLA-A29 heavy chain (A29) or human β₂-microglobulin (M), double transgenic mice carrying both human genes (A29M), and mice without any transgene. We then compared the incidence of retinopathy in these four phenotypes raised under identical housing conditions. A29-negative denotes nontransgenic mice and mice carrying only human β₂-microglobulin; A29-positive comprises double (A29M) and single (A29) transgenic mice.