<Tr> <Th> Aliases </Th> <Td_colspan="3"> CD4, CD4mut, CD4 molecule </Td> </Tr> <Tr> <Th> External IDs </Th> <Td_colspan="3"> MGI: 88335 HomoloGene: 513 GeneCards: CD4 </Td> </Tr> <Tr> <Td_colspan="4"> <Table> <Tr> <Th_colspan="4"> (hide) Gene location (Human) </Th> </Tr> <Tr> <Td_colspan="4"> </Td> </Tr> <Tr> <Th> Chr . </Th> <Td_colspan="3"> Chromosome 12 (human) </Td> </Tr> <Tr> <Td_colspan="4"> </Td> </Tr> <Tr> <Th> Band </Th> <Td> 12p13. 31 </Td> <Th> Start </Th> <Td> 6,786,858 bp </Td> </Tr> <Tr> <Th> End </Th> <Td> 6,820,808 bp </Td> </Tr> </Table> </Td> </Tr> <Table> <Tr> <Th_colspan="4"> (hide) Gene location (Human) </Th> </Tr> <Tr> <Td_colspan="4"> </Td> </Tr> <Tr> <Th> Chr . </Th> <Td_colspan="3"> Chromosome 12 (human) </Td> </Tr> <Tr> <Td_colspan="4"> </Td> </Tr> <Tr> <Th> Band </Th> <Td> 12p13. 31 </Td> <Th> Start </Th> <Td> 6,786,858 bp </Td> </Tr> <Tr> <Th> End </Th> <Td> 6,820,808 bp </Td> </Tr> </Table>

Cd4 is a characteristic surface marker and a result of which of the following