小中大
is your TNFa a mouse TNF? another thing is how is your dilution? seems this paper
J Virol. 2005 December; 79(24): 15405–15416
(polyclonal goat antibodies that recognize murine TNF-α (sc-1350, diluted 1:500 [Santa Cruz Biotechnology, Santa Cruz, CA], )
can tell you something.
did you use anti-goat secondary antiobody?