Gaithersburg-based MedImmune will gain 300 jobs as parent company AstraZeneca consolidates its overall global research and development operations, the companies announced Monday.

The announcement comes as AstraZeneca designated the Gaithersburg subsidiary one of three global research and development centers for the company, as well as the center of its marketing and specialty care commercial operations for the United States.

In January, AstraZeneca named Bahija Jallal chief executive of MedImmune and said its Montgomery County offices would serve as a primary location for the company’s biologics research and development.

In addition to Gaithersburg, AstraZeneca will maintain research and development hubs in Cambridge, United Kingdom and Mölndal, Sweden.

“The strategic centers will also allow us to tap into important bioscience hotspots, providing more of our people with easy access to leading-edge academic and industry networks, scientific talent and valuable partnering opportunities,” AstraZeneca chief executive Pascal Soriot said in a statement.

MedImmune counts roughly 2,000 employees in Gaitherburg and another 540 in Cambridge, Jallal said in an interview, including staff on both the science and business sides of the company.

Jallal said that biologics make up about 50 percent of AstraZeneca’s drug development pipline and most of that research takes place in Gaithersburg, meaning MedImmune should continue to play a central role in AstraZeneca’s growth as a company.

AstraZeneca paid $15.6 billion for MedImmune in the summer of 2007, a hefty price tag that to date remains unrivaled by other local biotechnology acquisitions.

“AstraZeneca frankly placed a huge importance into MedImmune when they bought MedImmune and I think since then there was a serious commitment,” Jallal said. “This is another step in that commitment to MedImmune . . . and the investment they’re doing in biologics.”

The restructuring announced Monday will result in 1,200 jobs leaving the company’s Wilmington, Del. location. About 650 of those positions will be eliminated, 80 will go to Boston and another 170 will be relocated to other AstraZeneca sites.

“The proposals are designed to co-locate teams to improve collaboration and put science and the patient at the heart of everything the company does,” AstraZeneca said in a statement. “The changes will also simplify the company’s global site footprint.”