Cyril S. Stulberg

Autoimmune hemolytic anemia: Natural history and viral-immunologic interactions in childhood

Long-term studies of autoimmune hemolytic anemia (AIHA) in twenty-eight unselected children showed three main patterns: I, low age, acute onset, early full recovery, normal immunoglobulins; II, wide age range, acute onset, chronic course, occasional purpura, eventual recovery, abnormal immunoglobulins; III, indeterminate onset, frequency of growth failure, purpura, neutropenia, massive lymphadenopathy, various illnesses and complications, high mortality, indefinite duration, immunoglobulins abnormal, mostly IgA deficiencies. Chromosomal abnormalities were common in all groups. Primary or recurrent cytomegalovirus infections were a common finding and apparently implicated directly in hemolysis and autoimmunity, susceptibility depending on lack of acquired immunity in group I and gradations of immunodeficiency in groups II and III. Other occult viruses may be involved. Autoantibodies correlated poorly with hemolysis and appeared to indicate variable secondary response to virus-related antigens, depending on host immunologic capacity, rather than intrinsic disturbances of erythrocyte immune homeostasis. The observations support the hypothesis that the basic disturbance in AIHA is an immunologic handicap predisposing to occult viral infections which in some as yet undetermined manner cause hemolysis and may induce autoantibody formation.

Comparative behavior of 16 ECHO virus types in fibroblast-like and epithelial-like human cell strains.

Summary The susceptibility ranges of a fibroblast-like and 6 epithelial-like human cell strains to 16 ECHO virus types have been described. All of these ECHO viruses except type 10 multiplied in the fibroblast-like cell strain (Detroit-196 Fb-L). In contrast, an epithelial-like strain (Detroit-196 Ep-L) evolving from the Fb-L strain, as well as 5 additional Ep-L cell strains, either were refractory or had narrow susceptibility ranges. The significance of differences in morphology with respect to virus susceptibility was discussed.

Purification of mouse poliomyelitis virus by methanol precipitation at low temperatures.

Conclusions Although at first glance the data may appear rather inconsistent, closer inspection reveals that the results are consistent when consideration is given to the experimental error involved in some of the methods. The variation in the nitrogen determinations of the crude virus suspensions were thought to be due in turn to expected variation in the amount of protein removed in the freezing and thawing steps. Estimations of the degree of purity have been presented in terms of the amount of nitrogen eliminated from the crude sample. Since purified normal brain gave nitrogen values which bore a close similarity to those obtained with purified infected tissue, it can be seen that the so-called purified fractions still contain a large amount of normal brain protein. There is no doubt that the non-viral protein greatly overbalances the viral proteins in the purified fraction. However, a relatively large amount of protein is removed during the procedure, as compared with the amount removed in the ultracentrifugation methods of purification cited by Beard.1 The activities of crude and purified virus fractions, with a few exceptions, remain fairly constant, indicating that most of the active virus is recovered. Although the titrations may not be accurate enough to determine the exact yield, they indicate that in many of the determinations 100% of the virus appeared to be recovered. The number of infectious units of virus per milligram of nitrogen depends, in part, on the original titer of the virus, and therefore is a relative value. When the methanol precipitate was held at −4°C for 4 hours the yield of virus was greater. Apparently no significant difference resulted from the use of 25% or 30% methanol. Also, the use of buffers at pH 5.1 or pH 5.6 to wash the precipitates did not seem to appreciably alter the results. One step that did result in the reduction of nitrogen was the immediate freezing of the final precipitate at pH 7 before it went into solution. Upon thawing, insoluble protein was removed by centrifugation.

Distemperoid Virus Interference in Canine Distemper

A distemper virus modified by ferret passage so as to become a harmless vaccine for foxes and dogs exhibits the interference or cell-blockade phenomenon with respect to a virulent distemper infection in foxes. Ten control foxes receiving virulent distemper virus died, while 30 foxes receiving distemperoid virus in addition lived.

Susceptibility of the gray fox to fox encephalitis.

Summary The results indicate that the gray fox is relatively resistant to fox encephalitis virus virulent for red foxes. It appears that the virus will regularly infect the gray fox to produce a symptomless infection, but only occasionally will symptoms appear that resemble the disease in red foxes. A virulence gradient of this virus for related species can be postulated whereby in the family Canidae the closely related dogs and coyotes (Cants) and red foxes (Vulpes) are most susceptible, the more distantly related gray fox (Urocyon) less susceptible, and those species which are earlier offshoots of the canines, such as the black bear and the raccoon, are the least susceptible to fox encephalitis.

Susceptibility of the bear to fox encephalitis.

Conclusions The intra-oeular inoculation of two bears and the intramuscular injection of a third with fox encephalitis virus indicate that the black bear (Euarctos americanus) is only slightly susceptible to this virus infection. Since the bear, like the raccoon, is an offshoot of the canines, the pathogenic properties of fox encephalitis virus derived from foxes seem sharply confined to the canine family.

Cell-blockade in canine distemper.

Summary A modified ferret-passage distemper virus exhibits an interference, or cell-blockade, phenomenon with respect to a virulent distemper virus in foxes. If the virulent virus is inoculated intranasally, as occurs in a natural infection, interference occurs when the modified virus is inoculated at the same time as, or after, the virulent virus. If the virulent virus is inoculated intramuscularly, the virulent infection can be blocked off by the modified virus only if the modified virus is given before, or at the same time as, the virulent virus. After an intramuscular injection of a virulent virus, any effect of the modified virus is in turn blocked off. The results appear to be determined by the virus that seeds the most tissue cells first. In the case of intranasal inoculation, the distemperoid virus seems to have a definite therapeutic effect during the incubation period and in the stage of early symptoms.

Purified human poliomyelitis virus; infectivity for cynomolgus monkeys.

Summary Human poliomyelitis virus in the form of infected monkey cord was purified by methanol precipitation at low temperatures. Titration by intracerebral inoculation in cynomolgus monkeys indicated no appreciable loss in activity of the virus during the purification procedure. It was shown that purified virus was infective for cynomolgus monkeys when administered by the oral route.