Do not italicize in regular usage. Capitalize only when referring to a proper name.
Thank you for supporting your alma mater.
The Citadel Alma Mater (name of song).
Altman Athletic Center
Named for the William M. Altman, Jr. family, the center at the south end of Johnson Hagood Stadium provides locker facilities and hospitality rooms.
alumni
Use the word “alum” to denote a single graduate, male or female. “Alumnus” refers to a single male graduate, “alumna,” to a single female graduate. The word “alumni” is plural and should only be used to refer to a group of male graduates or mixed group of graduates. The plural for female graduates is “alumnae.”
Alumni Association
Upon second reference, can be referred to as just the “association.”