Nucleotides 38 through 120 of the second exon were replaced with a stop codon followed by an IRES-EGFP and a floxed neo cassette. The neo cassette was subsequently removed by cre-mediated recombination following a cross to mice carrying the cre gene driven by a beta-actin promoter (allele not specified). The absence of protein product was confirmed by western blot analysis on proteins extracted from the lymph nodes and spleen. (J:126345)