Table 1.

Serological cross-reactivity for the H3 viruses after priming with the H1 viruses

Serological test	No. of positive mice/no. of mice primed
	H1wt serum		H1ova serum
	Against H3wt virus	Against H3ova virus	Against H3wt virus	Against H3ova virus
Hemagglutination inhibition	0/5	0/5	0/4	4/4 1:35 average titer
MDCK virus neutralization	0/6	0/6	0/6	3/6 1:100 average titer of positives
Embryonated hen egg neutralization	0/5	0/5	1/4 >1:40 average titer of positives	4/4 >1:40 average titer

The hemagglutination inhibition and neutralization tests utilized serum taken at least 7 weeks after i.p. priming with the H1wt and H1ova viruses.