We currently call CICS Main frame programs via Cobol.net using the CICS universal client.
We are wondering if it is possible to call them directly from C#?
Accessing CICS from Microsoft .NET applications using CICS Transaction Gateway
CICS v3 and later does SOAP and REST web services, if that's direct enough for your purposes.
I'll chime in with Host Integration Server. I used to use it and it works quite well.
Accessing CICS from Microsoft .NET applications using CICS Transaction Gateway