The EB Herpes.like Virus : Etiologic Agent of Infectious Mononucleosis?

Mononucleosis? The recent announcement by the Doctors Henle of Philadelphia of the finding of an antibody against the EB virus in the sera of all cases of infectious mononucleosis ( TM ) studied’ was the source of some excitement in immunologic, oncologic, and hematologic circles. In a prime example of serendipity, the Henles, who were testing various sera for antibody to this newly-discovered herpes-like virus, found that one of their technicians, previously negative, had developed a positive anti-viral antibody when she became ill with infectious mononucleosis. This led to a large scale study and eventually to the strong implication that the EB virus was the long-sought-for etiologic agent of IM. The EB virus, a “new” member of the herpes group of viruses, had previously been cited as the probable cause of the Burkitt lymphoma.2 It was first found by electron microscopy in cells of Burkitt lymphoblasts, and its presence was confirmed in various cell strains in tissue cultures from cases of that disease. Epstein and Barr ( EB ) and their collaborators prepared viruses from bulk cultures of their EB 3 strain of Burkitt lymphoma lymphoblasts and then, using purified viral cultures, were able to produce an antibody specific for the EB virus by immunization of rabbits.3 With the use of an immunofluorescent technic, the anti-serum gave a “brilliant apple-green fluorescence” with cells of EB 3 Burkitt lymphoblast cultures, but not against normal human lymphocytes, nor against cells infected with other viruses, including those of other herpetic viruses. Search for a viral agent in the Burkitt lymphoma has been pursued vigorously, especially since epidemiologic studies indicated the possibility of an insect vector for an infectious agent.4 In addition to the EB virus,5 at least two other viruses have been implicated in the disease including that of herpes simplex (Sarah Stewart)5 and reo virus 3 (Stanley).6 No direct evidence that any one of these agents is the causative agent of the Burkitt lymphoma has thus far been obtained. In IM, the strong presumption that a virus is the cause of the disease has l)een held for a number of years, especially since no other type of infectious agent has been demonstrated. Much inferential data are present to indicate that the disease might be transmitted through rather vigorous osculatory maneuvers,7 perhaps more prevalent in adolescents and young adults than in children or older people. Although attempts to induce the disease in volunteers and monkeys by injections of blood, saliva, and other secretions have been largely unsuccessful, they have not ruled out a viral agent.8 #{176} Does then the recent work of the Henles indicate that the EB virus is etiologic in IM? It should first be stated that the Henles did not, in their first studies, find