Force of Nature- The Life of Linus Pauling

by Thomas Hager

  But the most exciting news was Campbell's success by late 1941 in making artificial antibodies. The concept, based again on Pauling's 1940 paper, was that any globulin in the blood could be turned into a specific antibody by denaturing it, then allowing it to re-form around the desired antigen. This, Pauling wrote Weaver excitedly in November, was exactly what Campbell had accomplished with beef globulin. They had created the world's first artificial antibodies. Pauling concluded his letter by saying with some understatement, "I think that this synthesis of antibodies in vitro can be considered to be pretty important." He did mention that he considered it important enough to apply for a patent on the process.

  Campbell's experiments, however, were not as definitive as Pauling made them sound. Campbell was creating something that acted like an antibody—a protein that did, at least in Campbell's hands, bind specifically to a target antigen—but the yields of this specific product from beef globulin were low and variable. In the best cases only about one-eighth of the "manufactured antibodies," as Pauling called them, stuck to the antigen. The strength of the attachment between antibody and antigen was also less than that of natural antibodies, and the ratio of antibody to antigen in precipitates was much lower.

  But that might all be explained by imperfections in the synthesis technique. The evidence might be weak, but it was there, and it fit Pauling's theories of antibody formation and of protein structure in general, with his idea of long, hydrogen-bonded chains forming into a variety of shapes. It corroborated his vision of the world. It should work.

  He decided that it did work. The successful preparation of artificial antibodies raised all sorts of interesting possibilities. In wartime there was a crying need for all kinds of medicines, and artificial antibodies held the promise of being the most potent medicines in the world. By patenting the process, Pauling showed that he understood the commercial value of his discovery, and he underlined his sense of the money involved by taking an unusual step. In March 1942 he wrote and distributed through Caltech a press release announcing that his laboratory had successfully prepared artificial antibodies. In it he noted that while it was not yet known if his discovery would be useful in medicine, the studies did "open up the possibility of a new method for use in the fight against disease."

  Announcing a discovery of this importance in the popular press before anything had been published in a scientific journal was almost unheard of. But it worked to Pauling's advantage. The response was immediate. Wire services picked up the story and distributed it widely. Science ran the story in its news section, telling the research community: "For the first time in medical history, disease-fighting substances known as antibodies have been formed artificially in laboratory flasks." The editors of the Journal of the American Medical Association noted the work approvingly and looked forward to the day when networks of artificial immune human plasma banks would dispense Pauling's products. Representatives from pharmaceutical companies contacted Pauling, offering financial and technical help.

  But Pauling wanted more strings-free grant money to perfect his preparatory techniques before commercializing them, and he used the burst of publicity following his press release to make certain he got it. There were two interested agencies, the OSRD's Committee on Medical Research and the Rockefeller Foundation. Pauling played them off against one another, telling the committee of his findings while simultaneously tempting Weaver with the "reasonable possibility" of developing a treatment of value against disease. Weaver got caught up in the excitement. On very short notice the Rockefeller Foundation granted Pauling thirty-one thousand dollars for his work in immunology, including twenty thousand dollars to perfect the manufacturing of artificial antibodies.

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  Not everyone, however, was enthusiastic. In April, Pauling wrote: "Not many people have written in for information about our experiments on the in vitro production of antibodies. Perhaps they have been too skeptical." He was right. The immunological community withheld its opinion until August, when Pauling's first complete papers on artificial antibodies appeared in Science and the Journal of Experimental Medicine. The published work showed that Pauling still had a long way to go to prove that he had done what he claimed. The experiments were described so sketchily that it was impossible to accurately replicate the work, and his control experiments looked weak. When Landsteiner and others tried to duplicate the work, they failed.

  Despite growing skepticism, Pauling still believed he was right. There were some new positive results: He and Campbell made artificial antibodies to Pneumococcus antigens and found that they had at least some measurable protective effect against disease when used in infected mice. But there were other signs that pointed to trouble. Campbell seemed to be the only man who could make artificial antibodies. Students and postdoctoral fellows working under his direction had no luck at all. After three months of trying, one research fellow wrote Pauling, "You have my good wishes in your endeavor to prepare artificial antibodies, but I must confess to a feeling of pessimism. . . .Frankly, I am not impressed by experimental procedures which work sometimes but which do not at other times, and no cause can be assigned for the failure."

  By early 1943 the Rockefeller Foundation was getting nervous. Frank Blair Hanson had taken over some of Weaver's duties in the natural sciences division, and he was less enthusiastic about Pauling than Weaver was. As time neared to renew the immunology grant, Hanson surveyed the nation's leading antibody experts to find out what they thought of Pauling's ideas. The responses were not encouraging. One respondent declared flatly that artificial antibodies had not been produced in Pasadena; another worried that Pauling "is not always critical of his own work." Landsteiner, while still supporting Pauling's general theory of antibody formation, told Hanson that if he were a betting man, "he would think the chances less than 50-50 that Pauling has manufactured antibodies." Famed microbiologist Rene Dubos summed it up: "Professor Pauling's views have received wide notoriety because of his great prestige in the field of chemistry. There are many of us, however, who feel that his claims . . . are based on very insufficient experimental evidence."

  Hanson became openly skeptical himself, asking Pauling why, given the inconclusive results after a year's effort, his funding should not be decreased. Pauling did not know what to answer. There was just enough success to be tantalizing but too many failures to make things clear. After proclaiming to the world his success with artificial antibodies, he now had to admit that he was "disappointed" in their inability to fully protect animals. In further correspondence, he began downplaying the importance of artificial antibodies in his overall research scheme. The Rockefeller Foundation responded by cutting his special funding for the project by more than half. At the same time, Pauling quietly abandoned his patent application for manufactured antibodies. He would never publish another paper on the subject.

  But neither would he retract his work. He had no idea why Campbell's tantalizing experiments promised success and delivered only confusion. His theory, he felt, was correct. And the small production of artificial antibodies that he had seen in Campbell's results must also be right. If it was not, someone would publicly prove it wrong.

  No one did, during the war or for years afterward. In private, the top immunological researchers of the day decried Pauling's work and faulted him for not disavowing it. But they would not make their criticisms public. Only Elvin Rabat, a young immunologist just starting his career, was brash enough to attack Pauling's results in print, writing in a review article that what Pauling and Campbell were seeing was nonspecific binding of antigen and globulin; Campbell, he said, had used so much globulin in his tests that the proteins stuck together randomly, dragging down some antigen with them. Privately, a number of more senior immunologists thought Kabat was probably right. So why was he the only one to publicly critique the work? As Kabat later said, "Pauling was such a powerful figure that most people did not want to get into criticizing him."

  The silence ensured that Pauling's r
eputation would not suffer too much from his unsuccessful flirtation with artificial antibodies. Only those immunologists most familiar with the field and the officials at the Rockefeller Foundation were aware of how significantly he had oversold the idea.

  Pauling for his part would always believe that the work he and Campbell had done was valid. Fifty years later, Pauling still insisted: "We did succeed in creating artificial antibodies—very weak ones, but still with specificity."

  Why had the miraculous substances appeared only in Dan Campbell's flasks? Years later, long after giving up on the quest for artificial antibodies, Campbell offered an explanation to his close friend Ray Owen, then a member of the Caltech biology division. An overeager laboratory assistant, he said, had shaded the results to fit what he thought his bosses wanted to see. The whole incident occurred, Campbell said, "because of some technician who wanted the results to please the professor."

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  The failure of artificial antibodies should not obscure the importance of Pauling’s other immunological research. After the beginning of 1943, he returned to more fundamental questions and, working with Pressman and Campbell, began putting together a string of solid achievements. The group published more than twenty articles over the next few years, providing strong evidence for the bivalence of antibodies and the importance of specific molecular shapes in explaining the binding of antibody to antigen. By using better-defined synthetic antigens than Landsteiner's and new quantitative techniques for measuring the reaction with antibodies, the Pauling lab proved definitively by war's end that the binding of antibody to antigen took place because the fit between them was complementary. Their work supported and extended Ehrlich's idea of lock-and-key binding, showing beyond a doubt that antibody and antigen bound to each other by fitting together like two pieces of a molecular jigsaw puzzle.

  But what held them together? Studying the moderate amount of energy required to break the bond between antibody and antigen had already convinced Pauling that strong chemical bonds—covalent or ionic—were not involved. A new picture emerged in his mind. By comparing the reaction between an antibody and various antigens that differed in defined ways from the original target, Pauling's team found that changing as little as a single atom in an antigen could have a significant effect on the strength of binding. The fit, in other words, had to be astonishingly precise.

  This close nuzzling together of molecules, atom to atom, brought into play another kind of glue, the van der Waals attraction between atoms. The van der Waals force, named for the Dutch scientist who outlined its effect in gases, was weak—one-tenth to one one-hundredth the strength of a covalent bond—and nonspecific, operating between almost any pair of atoms brought into close contact. Fritz London in 1930 had explained it in quantum-mechanical terms as a weak electrical attraction produced when two atoms brought close together perturbed each other's electron cloud. Pauling was familiar with it through his crystallographic work: A covalent bond held two iodine atoms tightly together as a molecule, but the molecules were bound together into a crystal by the van der Waals force. The important thing for antibodies was that the van der Waals force decreases geometrically with distance, making it operative only at very close proximity. With only a few atoms involved, it does not add up to much, but if giant molecules like proteins brought a good deal of their surfaces together, Pauling realized, the total van der Waals force could add up to something significant, enough to bind the two molecules together. Postulating this as a major factor in antigen-antibody interaction also meant that pushing the molecules apart even a little—Pauling's lab found that creating a bump on an antigen's surface that pushed the antibody away the equivalent of a fraction of the diameter of a single atom was enough —would measurably weaken the binding force. If the misfit was more pronounced, the antigen and antibody let go of each other.

  Pauling found that this weak, nonspecific force, combined with some hydrogen bonding and the attraction of oppositely charged polar groups, added up to the highly specific binding of antibody and antigen. And it all worked because of structure. Precise, complementary shapes were all-important. In immunology, at least, Pauling became convinced that molecular structure determined biological specificity.

  This was an important insight into the interactions of molecules inside the body. It spoke not only to antigen-antibody matches, but to the bigger theme of biological specificity. The work was valuable enough to keep Pauling in the forefront of immunological research despite his failure with artificial antibodies. His direct template theory of antibody formation also continued to be well accepted. It was so straightforward and sensible that despite its drawbacks it would reign as the most plausible theory of antibody formation for the next fifteen years. Even in private the same immunologists who criticized Pauling's work admitted that he brought new energy to the field, made significant findings, and stimulated useful discussion. It would not be until the mid-1950s that his direct-template idea would be supplanted by the advent of a new theory of antibody formation based on some surprising genetics. Only then would he finally be proven wrong about the way antibodies were made.

  But he was right about how they stuck to antigens.

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  Ava Helen, too, did war work. For a few months she served as a research assistant in the laboratory of a Caltech biologist searching for a way to make artificial rubber. She underwent training as an auxiliary firefighter and air-raid warden for Los Angeles County. She dug a victory garden in front of her home. There was political work to be done, too: The proposed internment of Japanese-Americans in 1942 struck her as a blatant violation of civil rights, and she volunteered her time to the local American Civil Liberties Union (ACLU) to fight it.

  At the same time, she maintained her role as mother and wife. She tried to keep the house in the hills a refuge from the war and its worries, although it was not easy. Every day, her children could hear booming explosions from one of Caltech's powder-research sites down below. In the middle of one night in 1942 the entire family was awakened by an air-raid scare. While Pauling counted the rounds of antiaircraft fire and estimated the heights of the searchlights, Ava Helen comforted the children.

  They needed comforting, Linus junior, sixteen years old when the war broke out, was, he said later, "a screwed-up adolescent in many ways." He was coming to grips with his relationship to a father he felt was both distant and demanding, a man he could never please, an emotional cipher with whom he could never feel comfortable. Pauling's idea of a father-son interaction was to bring home sample problems from his freshman chemistry text and try them out on high school-aged Linus junior—who felt humiliated when he couldn't do the work. Although he got reasonably good grades, Linus junior had trouble settling down in school, going through three high schools before ending up at Flintridge, an elite boarding institution a few miles from Pasadena. When he returned home in the summers, he felt himself a stranger, six years older than his nearest brother, closer in age to the graduate students and research fellows his father commandeered as baby-sitters than to his siblings. He was unsure of his future: Although Pauling did not push him, young Linus felt that he was expected to go into science, yet he did not want to compete with his father. By the time the war started, he had made up his mind to go into medicine, a field he felt was "allied closely enough with science to satisfy what I perceived as parental requirements." Then, at age eighteen, fresh out of Flintridge, he joined the air corps and left home.

  The other children were also having a tough time. Peter, also sent to boarding school at an early age, began to show signs of erratic behavior during the war years. One term he would bring home the best grades in his class at Flintridge, then fall into the B and C range the next. Despite a quick wit and verbal agility, his school reports became a litany of the same complaint: "He should and could do straight A's. . . . But his work is not nearly up to his capacity." Concerned about his progress, Pauling and Ava Helen finally took him out of Flintridge in 1945 and sent him to a p
ublic junior high school—where he easily got all A's in his core classes.

  Linda was growing into a beautiful child, the apple of her father's eye—when she could catch it. The baby, Crellie, was precocious and made much of. But the Sierra Madre house was isolated, and Linda and Crellin felt the absence of other children to play with. There was loneliness of another type as well: Their parents were often gone. Pauling was either on the road, at Caltech, or holed up in his octagonal study, where the children had strict orders never to disturb him. And while Ava Helen strove to be a perfect mother, she also enjoyed traveling and accompanied her husband as often as she could. They were gone for days or sometimes weeks at a time. The Baker Lectureship had taken the two of them to Cornell for four months, during which time they left Crellin, then a baby, and the other children at home in the care of an administrative assistant from the Chemistry Division, Arletta Townsend. Townsend became like a second mother, close to all three of the younger children, especially Linda.