Antigens of Rickettsia prowazeki. II. Activity in guinea pigs and exerimental vaccine production.
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Biomedical subjects
Publications and source records attributed to L F Barker.
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Studies were undertaken to evaluate the role of complement in the interaction between mycoplasmas and antiserum. A suspension of the A-1 strain of Mycoplasma gallisepticum in PPLO broth was incubated at 37 C with rabbit immune serum which had been heated for 30 min at 56 C. Samples were removed from the mixture at timed intervals for 1 hr for titration of the mycoplasmas in broth. When normal guinea pig serum was included in the mixture at a final dilution of 1:40, the titer fell rapidly from 10(6) to 10(2) organisms per 0.2 ml. When the guinea pig serum was heated for 30 min at 56 C or was omitted from the mixture, the immune serum did not reduce the titer. The rate of inactivation was related to the final concentration of antiserum and to the incubation temperature. The effect of the guinea pig serum was eliminated by the addition of 0.01 m sodium ethylenediaminetetraacetate or by prior absorption with an unrelated antigen-antibody complex. It was concluded that complement-like substances play an important role in immune inactivation of M. gallisepticum.
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A collection of 1,278 lots of immune serum globulin (ISG) prepared by 19 United States manufacturers between 1962 and 1974 were tested for the hepatitis B surface antigen (HBSAg) and antibody (anti-HBS). Ten lots (0.8%), all of which were produced between 1962 and 1965 by two different manufacturers, were weakly positive for HBSAg (by radioimmunoassay). Seven hundred and seven lots (55.3%) were positive for anti-HBS (by passive hemagglutination). In general, titers of anti- HBS in lots of ISG were low, and the prevalence of anti HBS positive lots varied considerably among different manufacturers. ISG prepared from placental material was more commonly positive for anti-HBS than was ISG prepared from plasma. There was a striking overall increase in prevalence and titer of anti-HBS in ISG lots prepared during 1973 and 1974. This probably reflects the effect of elimination of strongly HBSAg-positive plasma units with the onset of routine screening for HBSAg which began in 1972.
A collection of 1,985 lots of normal serum albumin (NSA) and 1,361 lots of plasma protein fraction (PPF) prepared between 1958 and 1974 were tested for the presence of hepatitis B surface antigen (HBsAg). Twenty-one percent of NSA lots and 71 per cent of PPF lots were HBsAg-positive by radioimmunoassay. There was considerable variation in frequency of HBsAg-positive lots among the 17 different manufacturers of NSA and the six manufacturers of PPF. In general, those lots prepared from volunteer donor plasma and placental material demonstrated lower rates of HBsAg-positivity than those prepared from commercial donor plasma. A striking decrease in the prevalence of HBsAg-positive lots of both NSA and PPF occurred during the period 1971 to 1973, coincident with the onset of routine screening of all plasma for HBsAg. Although NSA and PPF can be HBsAg-positive, they probably do not transmit type B hepatitis. Serologic tests for HBsAg and antibody to HBsAg revealed that albumin products prepared from infectious, icterogenic plasma were infectious prior to pasteurization, but that they no longer transmitted type B hepatitis after heat treatment at 60 C for ten hours.
In November, 1974, eight patients in three hospitals had pyrogen reactions associated with the infusion of 25% Normal Serum Albumin from the same lot. The reactions were recognized because the same physician or nurse observed several patients having recurrent reactions or because a single patient receiving several vials had consecutive reactions. The remaining albumin in three vials associated with reactions had apparent endotoxin concentrations of 4, 16, and 32 ng/ml and that 22 vials from recalled supplies had a median concentration of 4 ng/ml (range: 2 to 64) as determined by the Limulus amebocyte lysate test, but the lot again passed the rabbit pyrogen test. In a prospective study to determine the efficacy of the Limulus test in quality control, patients had their temperatures taken hourly during albumin infusions and the remaining fluid was tested by the Limulus assay. The albumin in 443 of the 662 vials infused (65%) gave a positive test and 311 of these vials (45%) had apparent endotoxin concentrations of 4 to 64 ng/ml, but no patient had a reaction. Because of the limitations of both the rabbit pyrogen and Limulus test, the detection of some pyrogenic lots continues to depend on hospital surveillance and reporting os suspect reactions.
Sera and questionnaires were evaluated retrospectively from 128 volunteer blood donors whose blood had been implicated in cases of clinically recognized post-transfusion hepatitis in recipients of one- or two-unit blood transfusion between 1971 and 1977. Serologic markers of hepatitis B virus (HBV) infection were found in 23 percent, compared to 9.7 percent of 3,230 prospective blood donors. The prevalence of antibody to hepatitis A virus was similar among implicated donors (44%), prospective donors (58%), and among those implicated donors with (41%) and without (44%) HBV markers. Among implicated donors, none had a history at the time of donation of having had clinically recognizable hepatitis, 93 percent had no history of prior blood transfusion, and 80 percent had normal hepatic enzymes. Data from this study confirm that non-A, non-B hepatitis has been a common form of posttransfusion hepatitis in recent years, since 77 percent of these implicated donors had no HBV serologic markers. In addition, these donors could not be distinguished by age, race, sex, history of clinical hepatitis or of prior blood transfusion, or in most cases by hepatic enzyme levels.
Sera and questionnaires from 3,230 prospective U.S. volunteer blood donors were obtained in an earlier study to determine the prevalence of serologic markers of hepatitis B virus (HBV) and hepatitis A virus (HAV) among prospective blood donors with or without a history of either hepatitis or blood transfusion. These sera were reevaluated using a radioimmunoassay for antibody to hepatitis B core antigen (anti-HBc). Anti-HBc in the absence of hepatitis B surface antigen (HBsAg) or its antibody (anti-HBs) was detected in 30 of 1,151 (2.6%) prospective donors with a history of hepatitis, compared to four of 1,086 (0.4%) with no history of hepatitis (p less than 0.001). Although end-point dilution titers of anti-HBc greater than or equal to 1:100 and the presence of IgM anti-HBc were more frequently detected among donors with a history of hepatitis than among donors with no history of hepatitis, the difference was not statistically significant. Unlike a history of hepatitis, a history of transfusion or a history of exposure to persons with hepatitis had no significant association with the detection of anti-HBc in the absence of other HBV serologic markers.
Using the technique of immune electron microscopy we have conducted hepatitis A infectivity studies in marmoset monkeys and chimpanzees. Marmosets inoculated with human serum containing the MS-1 strain of hepatitis A virus have developed hepatitis and seroconverted to 27 nm virus-like particles isolated from stools of humans in the early acute stages of hepatitis. Similar results have been observed through several marmoset subpassages, and the virus-like particles have been recovered from the liver of animals in the acute phase of hepatitis. Chimpanzees inoculated with stool filtrates containing the virus-like particles develop hepatitis with concomitant excretion of the particles in early acute phase stools and subsequent development of serum antibody to the particles. These studies provide evidence that the above particles constitute the virus of hepatitis A of the MS-1 prototype.
Two distinct antigen-antibody systems are associated with the hepatitis B virus (HBV): hepatitis B surface antigen (HBs Ag) and antibody (anti-HBs) and the more recently described hepatitis B core antigen (HBc Ag) and antibody (anti-HBc). Testing of serial serum samples from patients with type B hepatitis demonstrates the regular occurrence of anti-HBc during the course of this disease. In general, highest titers of anti-HBc are seen with prolonged circulation of HBs Ag as in the chronic carrier state. Titers of anti-HBc begin to fall with recovery from HBV infection and anti-HBc appears to be shorter lived than anti-HBs. As such, anti-HBc testing is important in documenting the occurrence of infection with HBV and is of great value in epidemiologic studies and in evaluating the safety and efficacy of hepatitis B immune globulin and HBV vaccines.
Evidence of natural infection with hepatitis B virus (HBV) in chimpanzees was followed by demonstration that this species provides a highly sensitive animal model system for experimental type B hepatitis. With rare exceptions, inoculation of sero-negative chimps with materials containing infectious HBV produces serologic evidence of infection including appearance of circulating hepatitis B surface antigen (HBs Ag) and subsequently development of antibody to HBs Ag and hepatitis B core antigen. Serum enzyme elevations indicative of liver damage occurred in 31 of 46 aminals infected to date. The antigenic subtypes of HBV in the inocula breed true in the infected animals, and HBV titers of sera containing the adw and ayw subtypes have been established as 10(7.5) infectious units/ml. Rhesus monkeys also provide a valuable animal model for type B hepatitis, but they appear to be less sensitive than chimps, and they do not develop evidence of liver damage.
Sera from individuals in an outbreak of viral hepatitis in a multifamily household, probably spread by contaminated food, were studied for antibodies to hepatitis A virus (anti-HAV), and selected acute phase sera were inoculated into marmosets. Significant rises in anti-HAV titers between acute and convalescent sera occurred in all of 15 individuals in the outbreak who experienced serum enzyme elevations and in one of 14 individuals whose serum enzyme levels remained normal. The remaining 13 individuals in the latter group had antibody levels in both early and late sera compatible with residual immunity from prior HAV infections and correlating with resistance to reinfection. Groups of marmosets were infected with acute phase sera from two of the cases; in both instances the inoculated sera contained substantial levels of anti-HAV. The marmosets developed specific anti-HAV seroconversions as well as enzyme elevations.