Antonio Brown 's fighting back against claims he tried to shoot and kill someone at a celebrity boxing match earlier this year, pleading not guilty to 2nd degree attempted murder ... an incident his attorney is adamant was nothing more than self-defense! AB hired Mark Eiglarsh ahead of his trial ... and the lawyer sent TMZ Sports a statement addressing the altercation at Adin Ross ' event, explaining he took the case because he "passionately believes in Brown's defense." "The actions he was