mon·o·va·lent 
(mŏn′ə-vālənt)
(mŏn′ə-vālənt)adj.
1. Immunology
a. Containing antigens from a single strain of a microorganism or virus. Used of a vaccine or serum.
b. Having only one site of attachment. Used of an antibody or antigen.
2. Chemistry Univalent.
mon′o·valence, mon′o·valen·cy n.