The TviA protein interacts in conjunction with the RcsB regulator protein at the promoter upstream of tviA to control the transcription of tviB -LRB- encoding an enzyme similar to GDP-mannose dehydrogenase involved a 2 , no agglutination ; 1/2 , weak agglutination ; 111 , strong agglutination ; 1111 , very strong agglutination .