Bello worked for the
University of Pennsylvania as a medical laboratory assistant from 1962 to 1980. She became a medical laboratory researcher at University of Pennsylvania in 1980 and later worked for the
Food and Drug Administration. In 1967, Bello became a founding member of the Philadelphia Chapter of the Daughters of Bilitis (DOB). Bello edited the DOB-Philadelphia newsletter with fellow activist Carole Friedman. They both influenced the decision to dissolve DOB and create the Homophile Action League (HAL) in 1968. Bello worked as the editor of the HAL newsletter which challenged
police harassment against the LGBTQ community. In 1968, Bello decided to become an activist after the
Philadelphia Police Department raided Rusty's Bar, a local lesbian bar, and arrested 12 women. After consulting with the
American Civil Liberties Union, HAL requested to meet with the police department. Due to her immigration status, Bello did not participate directly in the meetings, but drove the car for the HAL attendees. Bello attended the final two
Annual Reminder day protests in 1968 and 1969, having received U.S. citizenship in 1968. In 1980, Bello and fellow LGBTQ activists
Mark Segal and John Cunningham traveled to
Fort Indiantown Gap, Pennsylvania along with Spanish-speaking volunteers from the
Metropolitan Community Church to assist a group of LGBTQ refugees from Cuba on the
Mariel boatlift, known generally as "
Marielitos", to receive asylum and temporary housing with LGBTQ-friendly hosts in the United States as part of a settlement program initiated by President
Jimmy Carter. Bello volunteered for the
American Library Association's Gay Task Force under
Barbara Gittings and was a supporter of the
William Way LGBT Community Center where she served as co-chair. Bello served on the board of the Philadelphia Lesbian and Gay Task Force. She organized the predecessor of the AIDS Fund, From All Walks of Life. In a 2018 interview, Bello stated about her advocacy that: "In the future, I would like to get to a point in which your sexual orientation is irrelevant and is not taken more seriously than the color of your eyes." == Death ==