An isolated antigen wherein said antigen consists of amino acids 4-10, 18-36, 43-50, 63-71, 75-105, 109-117, 134-140, 145-157, 176-182, 184-201, 203-211, 215-225, 240-250, 262-284, 294-309, 313-319, 327-337, 350-356, 361-367, 372-393, 411-421, 428-451, 453-466, 487-492, 501-528, 535-553, 564-574, 592-605, 612-629, 631-640, 646-653, 658-666, 673-681, 713-718, 720-730, 739-749, 784-792, 821-826, 833-844, 853-863, 871-876, 885-894, 900-918, 937-950, 952-957, 972-990, 995-1001, 1024-1036, 1039-1044, 1049-1055, 1062-1089, 1091-1103, 1110-1121, 1123-1129, 1131-1151, 1157-1179, 1181-1201, 1204-1223, 1233-1244, 1269-1276, 1279-1286, 1294-1301, 1303-1309, 1315-1338, 1350-1362, 1373-1381, 1398-1406, 1412-1423, 1440-1446, 1458-1466, 1481-1487, 1492-1508, 1511-1518, 1528-1534, 1536-1547, 1553-1565, 1606-1617, 1619-1644, 761-781, 759-783, 582-1099, 761-781 or 59-783 of SEQ ID NO: