14 days after the last sensitization {HEAD ~ animals} were challenged with {TAIL ~ 100 μg OVA sc} 
14 days after the last sensitization { HEAD ~ animals } were challenged with { TAIL ~ 100 μg OVA sc }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL