The loud, jangling ring of a decades-old telephone interrupts a conversation going on in Barry Bloom's small office at Albert Einstein College of Medicine in the Morris Park section of the Bronx. It's a bit dusty in here, and the furniture has seen better days. In the middle of August, Bloom is entertaining yet another series of questions about his upcoming career change. Bloom answers the phone, listens intently, and nods his head; he smiles a couple of times. Finally he says that although it sounds interesting, he must decline the caller's invitation to speak at a future conference. He is unable to schedule anything past January 1, 1999, he explains, because after 34 years he is leaving Albert Einstein to become the next dean of the Harvard School of Public Health.

Dean Designate Barry R. Bloom, 61, is Weinstock Professor of Microbiology and Immunology at Albert Einstein and a Howard Hughes Medical Institute investigator. One of the pioneer researchers in cell-mediated immunity at the beginning of his career, Bloom is now recognized as a world-class immunologist. "He is a brilliant scientist and an exciting thinker," says John David, Richard Pearson Strong Professor of Tropical Public Health at the School. But Bloom has gone beyond bench science to become a kind of public health Renaissance man--strong in science, adept at politics, and moral of conscience. His friends and admirers say he has embraced each of these roles with gusto, passionately delving into the intricate subtleties of the body's immune system while at the same time forging his way through governmental and organizational politics. "Barry is always doing things that you don't expect a lab scientist to be doing," says Christopher Murray, professor of health economics at the Harvard Center for Population and Development, and a longtime friend and collaborator.

Bloom's career also exemplifies that altruistic streak that runs through public health--the ethos of doing the greatest good for the greatest number. He has become a tenacious advocate for the world's poorest people, both in the lab and out, tackling leprosy, tuberculosis, and aids. "He understands the necessity of a bully pulpit," says David about Bloom, who instead describes himself as merely "direct." At various times Bloom has taken on the World Health Organization (WHO), the U.S. Congress, and just about any other entity impeding progress on issues that are important to him, such as funding for tuberculosis research or vaccine development. "He's outspoken about appropriate things," says Anthony Fauci, director of the National Institute of Allergic and Infectious Diseases (NIAID). "We appreciate that."

"My credibility depends on being in touch with science...and that is something that I think is important for me to bring to the School."

Bloom's outspokenness and persistence have drawn considerably more supporters than critics. The Bloom fan club is large; it becomes almost routine to hear people say "I love Barry" at the first mention of his name. Says Richard Young, a genetics researcher at MIT whom Bloom persuaded to work for who, "Barry has a way of making most of the smart people around him his friends."

While making friends in his new position at the School may not be hard for Bloom, deciding how to juggle his many outside commitments just might. Bloom will retire from the governing board of the Institute of Medicine after two terms but hopes to continue as an adviser to the Joint United Nations Programme on HIV/AIDS (UNAIDS). Breaking his WHO connection would be especially hard; Bloom's work with the organization in tuberculosis, immunology, and vaccine development goes back more than 30 years. As chair of the Vaccine Advisory Committee of UNAIDS, he has played a critical role in the debate surrounding the ethics of AIDS vaccine trials. Bloom also chairs the board of trustees for the newly formed International Vaccine Institute located in South Korea, which is devoted to promoting vaccine development for children in the Third World.

What he most definitely will not give up, however, is his research. Unlike any dean before him, Bloom will bring his laboratory with him to his new post and continue his research into the immune response to tuberculosis. "My credibility depends on being in touch with science… and that is something that I think is important for me to bring to the School," says Bloom.

He has placed the bar high. Fauci at NIAID and Harold Varmus, head of the National Institutes of Health, are among the few who run research labs while also holding top administrative posts. But Bloom, say many, belongs in their league. "I've had the opportunity to observe some great leaders," says Young. "Barry has the characteristics of a great leader."

"I sensed from our very first conversation that this was someone with a powerful intellect and an equally powerful and broad-based commitment to advancing public health," says Harvard University President Neil Rudenstine.

Bloom's father was a Philadelphia physician whose two brothers and one sister were also doctors; a career in medicine seemed like a foregone conclusion for his only child. But Bloom started to get other ideas in high school after attending a summer science program at Jackson Lab in Bar Harbor, Maine. "I knew from that summer that that's where the action was--research," he says. The lab continued to beckon during his college summers, and by the time he graduated from Amherst College with an A.B. in biology in 1958, Bloom's mind was made up. His "fateful decision" not to attend medical school, however, did not go over too well with his parents, Bloom recalls.

But perhaps that dismay was short-lived, as Bloom won a scholarship to Rockefeller University on Manhattan's Upper East Side, the creme de la creme of science graduate universities. "It was a very heady and exciting time," says Bloom. "There was a conviction [at Rockefeller] that science was part of the general intellectual world and not a trade that made products. I shared that view, then and now." But before heading off to Rockefeller, Bloom took a post-college graduation trip to Europe that was as fateful as any turn in his science career. During that trans-Atlantic voyage in the summer of 1958, he met his wife, Irene. "I fell in love with her the minute I laid eyes on her," says Bloom. Irene Bloom is now the chair of the Department of Asian Studies at Barnard College and an expert on human rights issues and philosophy in Asia. Bloom says, "Absolutely, without question, she was the most beautiful person I'd ever seen. Nothing has changed since. She gets more beautiful and more smart every day."

In the early 1960s, scientists at Rockefeller and elsewhere were just beginning to understand the role that white blood cells--or, more precisely, T-cells--play in the immune response. Until that time much of what was known about the immune response was limited almost exclusively to antibodies. Once the importance of T-cells was appreciated, labs all over the country went full-tilt to try to characterize the complex interactions of this branch of the immune response. Following his graduation from Rockefeller in 1963, Bloom spent a year at the Wright-Fleming Institute in London with Nobel laureate Rod Porter and then went right to Albert Einstein, where he began his own set of experiments to unlock the mystery of what he rightly believed would be among the big breakthroughs in immunology. Bloom and a handful of researchers around the country (including John David, then a young upstart at New York University) were hot on the trail of a previously unknown kind of molecule, one that was produced by white blood cells but was not an antibody. "We knew that that was a paradigm shift and that it was important," recalls Bloom. "How important, what it was going to be good for, we had no idea-- still don't know. But it was exciting as hell, and it was terrific fun."

In a neck-and-neck race that both men graciously say ended in a tie during 1967 (they have been great friends ever since), Bloom and David identified a molecule called the migratory inhibition factor (MIF). Their discovery opened up a whole new frontier in immunology because mifs turned out to be just one of more than 50 types of cytokines. Cytokines act as chemical messengers and are what make possible a coordinated immune response to infection as they scurry among immune cells, "telling" them where and when to do their jobs. MIFs, for example, tell macrophages--large cells that engulf foreign material--to stay put at the site of infection.

WHO officials were intrigued by Bloom's cytokine work and in 1968 invited him to come to the organization's headquarters in Geneva to discuss leprosy. It was a disease, says Bloom, that he knew next to nothing about. Shortly after the who meeting, Bloom went to New Delhi, India, to encounter the disease firsthand. This trip and others to the Asian subcontinent were formative events in Bloom's life. To this day, he says he feels just as at home in India as he does in the United States (and colleagues say his Indian cooking is beyond compare). Nearly every patient with leprosy he saw there was begging on the street, recalls Bloom. It is human nature that pity rewards the most pitiful, so the patients with the worst deformities seemed to get the most handouts, he explains. But that logic set in motion a perverse pattern: the worst off and the most in need of treatment had the greatest reason--charity--to stay ill and not get help. Bloom says that seeing this human side of leprosy, and how economic and social circumstances can have such a dramatic effect on how a disease and diseased people are treated, made him realize that he couldn't pursue a career in basic science in splendid isolation from larger health issues. And he began thinking about vaccines and prevention.

"In every climate and every culture, there's been a unique horror and fascination with leprosy," he says. "It's the only disease that people were burned at the stake for. It's the only disease people were buried alive for. It has a unique history that has fascinated everybody. And at the same time, it's a skin disease that is immunologically mediated. And it's accessible. By a simple skin biopsy you can learn an enormous amount of what goes on in the disease, and because the disease is largely immunological, we believe we've learned a little bit about the regulation of the immune system in humans."

Back in Geneva, Bloom pushed for the formation of the Special Programme for Research and Training in Tropical Diseases (TDR) at WHO. Bloom says the idea was to put together all the programs for "diseases nobody cared about": malaria, trypanosomiasis (African sleeping sickness), schistosomiasis, tuberculosis, and leprosy. Today, under the guidance of Tore Godal, a Norwegian immunologist and pioneer leprosy researcher, the 26-year-old program has grown into one of WHO's major efforts.

Bloom says that TDR deserves much of the credit for reducing leprosy rates in India and around the world. The program bent over backwards to encourage scientific collaboration, making it a point to share information with anyone interested in leprosy research. It helped design effective systems for delivering treatment drugs. Meanwhile, the development and careful testing of drugs reduced the time needed for treatment from a six-month period to just a single day for some. Twenty-five years ago there were an estimated 12.5 million registered cases of leprosy worldwide. Today there are fewer than a million. What was done for leprosy "is a real model for how tuberculosis could be done," says Bloom, a point that he has made tirelessly to who officials.

"Barry has an extraordinary combination of talent and commitment, through which he has made fundamental contributions to international health and WHO," observes Godal.

"Whoa hoa!" Bloom lets out a cheer as he strides down the corridor outside his lab, his five-foot six-inch frame accelerating as he talks. He's holding a mock-up of a potential cover for Science magazine, which has just accepted a research paper from his lab. The article reveals for the first time that lymphocytes (white blood cells formed in the lymphatic tissue) can directly influence the survival of the pathogen that causes tuberculosis, Mycobacterium tuberculosis, once it has been engulfed by a macrophage. Bloom and his colleagues have moved one step closer to understanding why tuberculosis has the voracious power it does inside the body.

More than 350 research papers have emerged from Bloom's lab, which is as delightfully unkempt and cluttered as his office. "The Rockefeller experience certainly shaped how I run my lab," Bloom says with a smile. "My boss there was obsessively neat and compulsive, and as a result, in adolescent rebellion, I have been obsessively sloppy and un-neat." What is not sloppy is his research, which has teased apart, piece by piece and in painstaking detail, the mysteries of mycobacterium. (Mycobacterium leprae, which causes leprosy, and Mycobacterium tuberculosis are 2 of the 30 species in the mycobacterium genus.) Bloom and Bill Jacobs, his close collaborator at Albert Einstein, have helped decode the genetics of mycobacterium and developed a simple yet innovative method for testing the drug resistance of tuberculosis strains by using genes from fireflies.

As a human disease, tuberculosis is thought to be eons old. As an object of scientific research, it is over a century old; Robert Koch first isolated Mycobacterium tuberculosis in 1882. Despite this long track record, in recent years tuberculosis has not been a hot area of biomedical research. It is notoriously difficult to study. Tuberculosis researchers usually need a biosafety-level 3 lab because the disease is so highly infectious. The germ's tough, waxy coat makes it impermeable to normal substrates and compounds, and it grows slowly in culture. As a health problem, tuberculosis afflicts primarily the very poor in this country and the Third World.

So Bloom has had to work hard to convert people to the tuberculosis cause. He does it with a reputation for research achievements that places him in the world's scientific elite. He does it with enthusiasm, squared--which equals zest, minus any pretension or airs. Bloom's energy is obvious even to the first-time visitor. In conversation he moves in jumps and starts, focusing on an explanation of some arcane scientific problem and then, remembering an amusing story, erupting into a full belly laugh. His lab parties are famous. "As good as his science is, his potluck lab meetings outdid anything he has done in research," kids Edward Schwartz, a former post-doctoral student. "He convinces you that TB is the cutting edge of immunology," says JoAnne Flynn, another former postdoc.

Bloom also wins converts the old-fashioned way, with moral suasion. "Barry has made it very concrete to me," says Jacobs. "The majority of the world's people live in the Third World. They are very poor. We've got to do something about them." As for Bloom, he says he is a believer in "Lost Causes" and then quotes T. S. Eliot: "If we take the widest and wisest view of a Cause, there is no such thing as a Lost Cause, because there is no such thing as a Gained Cause. We fight for Lost Causes because we know that our defeat and dismay may be the preface to our successors' victory, although that victory itself will be temporary; we fight rather to keep something alive than in the expectation that anything will triumph." In public health, that is both literally and metaphorically true.

Curbing tuberculosis is one of many such "Lost Causes," says Bloom, adding disease prevention and equity in health and human rights to the list. "The most important thing is to cherish the pursuit," he declares.

But as if to put the brakes on runaway hagiography, Bloom says, "I don't go into the world every day and say, "How am I going to be Mother Teresa and help the poor and starving of the world?" I have curiosity, I have an interest. And there's a reciprocity in that the world impinges on what I find exciting and intellectually stimulating, and that stimulates an interaction of what can I do that would be of interest and might have sound practical benefit."

Bloom remarks that when he came to Boston to be interviewed for the dean's job, he kept hearing this odd expression, "every tub on its own bottom," which is Harvard-speak for each of the university's nine professional schools being independent, especially when it comes to fund-raising. Bloom raises an eyebrow, says he is looking forward to working with the deans of the other schools, and proposes a revision: "A rising tide lifts all bottoms."

Bloom says he has found the same kind of fascinating variation and adaptation at the School that he has witnessed in his 40 years studying the immune system. "This is a School that is its own generator of diversity," he says. "It's got an incredible diversity of people, interests, projects, disciplines, and I just find that very exciting."

"The dean is a storyteller. The School of Public Health has wonderful stories. It's my responsibility to learn those stories and to tell them compellingly."

What will Bloom do as the new keeper of this generator when he officially assumes the deanship on January 1? Polite and ever politic, he won't say exactly--or at least publicly. Declaring that it's unwise to devise a rigid plan of action until he's had the opportunity to meet and talk with the faculty, he has dropped only a few hints. He envisions a greater role for programs and projects of international scope.

Undoubtedly he will be interested in the School's work on tuberculosis and other infectious diseases. But Bloom also says that he is interested in learning more about the social science aspect of the work done at the School in departments such as Health and Social Behavior and Maternal and Child Health. "Barry is very effective at bringing people from one discipline into areas ruled by other disciplines and making them all work together," notes Young, the MIT geneticist.

One area that he does intend to beef up is the School's communications efforts to better translate and convey the objectives and accomplishments of public health--to the public all the way up to funding organizations and government bodies. Somewhere that message has been lost, he comments: "When an article appears in the New York Times that somebody has a drug that's shown to work in something, it's the doctor and the patient shown smiling after the drug has done its thing. But who designed the trial? Who analyzed that trial? Who did the statistics? The process by which you actually acquire knowledge I don't ever remember having seen mentioned. And that's what we do at the School of Public Health."

"The dean is a storyteller," he adds. "The School of Public Health has wonderful stories. It's my responsibility to learn those stories and to tell them compellingly."