test
node1
BFO:0000003
occurrent
node1->node1
node5
BFO:0000015
process
node1->node5
node2
BFO:0000001
entity
node2->node1
node3
GO:0008150
biological_process
node4
GO:0002376
immune system process
node3->node4
node6
GO:0019882
antigen processing
and presentation
node4->node6
node5->node3