Recent Adenovirus Isolates Exhibiting Broad Intratypic and Intertypic Antigenicity.

From the 43 adenovirus strains recently isolated from material collected in Pakistan, a number of antigenic variants were recovered. Strain Karachi-1 was found to be closely related to adenovirus type 21 by hemagglutination-inhibition but was significantly different in neutralization tests (Nt). Karachi-3 was antigenically related to adenovirus types 14 and 16. By HI the reaction between type 16 and Karachi-2 was clear, although by Nt significant differences were noted. Karachi-3 was not inhibited in the HI test by either type 3 or type 7a antisera but was found to be predominantly type 3, with a low level two-way cross with type 7a? when tested by Nt. Karachi-4 was found to be a hemagglutinating strain of adenovirus type 25, unlike the prototype in our hands.