Immunogen sequence: REGFLDTLVV LHRAGARLDV RDAWGRLPVD LAEE Antigen sequence identity: Mouse 97%; Rat 91%. The four known 15-to 19 kDa INK4 proteins (p15INK4b, p16INK4a, p18INK4c andp19INK4d) bind and inhibit CDK4 and CDK6 but not other CDKs, including cyc