Grapes in Revelation 14

A student, Amy Mertens, points out that the vine in Revelation 14 is bearing fruit, and thus is an unlikely symbol of the wicked or of apostate Israel. Jesus came looking for fruit on Israel’s fig tree and found none; why would we expect it to be found on the vine? It is certainly possible, given the OT uses of vine imagery for Israel, that the grapes of Rev 14 are faithful Jews, martyred for their faithful witness to the Messiah they had long expected. In any case, the vine of Revelation 14 must be the fruitful vine in the True Israel, Jesus.