15. The commonest mode of transmission of HIV is
A.parenteral
B.perintal
C.sexual
D.oral

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16. The cells most oftenly infected by HIV are
A.Null cells
B.CD8 + T lymphocytes
C.CD4 + T lymphocytes
D.None of these

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17. Which of the following is the spike antigen of HIV-I?
A.gp 120
B.gp 140
C.gp 36
D.gp 41

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