Writing Reply-to for mail sending

1.From, 2.Reply-to, 3.CC, 4.BCC, 5.Reply-to

mb_language("Japanese");
mb_internal_encoding("UTF-8");

$email = "xxx@example.com";
$subjet = "test";
$body = "this is test \n";
$to = 'yyy@example.com';
$header = "From: $email\nReplay-To: $email\n";

mb_send_mail($to; $subject, $body, $header);