I think it should be the University's responsibility to provide you with an antivirus client, wether it be Mcafee, Norton, Sophos or whatever.
It is their servers and internal security they are concerned with, not your personal computers'. Large organisations such as universities can purchase vast numbers of licences in bulk for pennies compared to a single licence subscription, if your university doesn't do that then I suspect they are either being cheapskates, or possibly they are not very au fait with current technology, and wouldn't notice if you had antivirus installed or not.
Mcafee ePolicy Orchestrator (the enterprise managing antivirus server) has an optional component called system compliance checking, which will let you restrict computers from joining the network until they match your set criteria, for example up to date virus definitions. I wouldn't expect universities to be using that feature because of the number of different systems connecting, but blocking computers without antivirus is certainly possible to do.