we confirmed that the performance of the 
combination of our deep learning framework and the 
representation of the protein features as PSSMs was 
mostly  superior  to  combinations  of  other  machine 
learning and pre-trained  feature embeddings. While 
we found that our model that was trained on a given 
source  human-viral  interaction  data  set  performed 
dismally in predicting protein interactions of proteins 
in a target human-virus domain, we  introduced two 
transfer learning methods (i.e. frozen type and fine-
tuning  type).  Notably,  our  methods  increased  the 
cross-viral  prediction  performance  dramatically, 
compared to the naïve baseline model. In particular, 
for  small  target  datasets,  fine-tuning  pre-trained 
parameters that were obtained from larger source sets 
increased prediction performance.  
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