A re-examination of the single radial haemolysis technique for the assay of influenza anti-neuraminidase antibodies in human sera

Summary A new study is described of the use of single radial haemolysis (SRH) for the measurement of antibodies to influenza virus neuraminidase (NA). The technique is known to be consistently successful in the assay of anti-haemagglutinin (HA) antibodies, subject only to the condition that the indicator virus belongs to an appropriate serotype. Its adaptation to the measurement of anti-NA is, however, more difficult. The virus used must be a recombinant which contains a specific NA and an irrelevant HA. However the present experiments showed that the two recombinants MRC-3 and X-38, which contain the same NA but a different HA, gave different results. Other properties of recombinants, including rates of attachment to and elution from red cells, many affect the results. The chemical NA-inhibition test (NI), although requiring the use of antigenic hybrids, did not produce these discrepancies. However it appears possible to exploit the simplicity and convenience of SRH for mass survey of anti-NA, if individual hybrid recombinants can first be shown to yield results comparable to those obtained by NI.With 2 Figures     

Neuraminidase and resistance to vaccination with live influenza A 2 Hong Kong vaccines

Thirty-seven volunteers were inoculated intranasally with living attenuated influenza A2 viruses. Rising titres of circulating antineuraminidase (AN) were detected in 14 of 17 infected volunteers. AN was also found in nasal secretions. Statistical analysis showed that there was a correlation between the titres of haemagglutination-inhibiting antibody (HI) and AN in nasal washings, and between AN in blood and washings. Resistance to infection could be predicted from antibody titres in 29 of 37 volunteers and blood AN alone predicted the outcome of 25 volunteers.     

Calcium channel blockers: nursing care for hypertension

Calcium channel blockers are gaining wider use in patients with cardiac disease, particularly hypertension and angina. The nurse must be aware of the actions, side effects, and interactions of these agents if they are to be administered safely.     

Plasmid DNA vaccines: tissue distribution and effects of DNA sequence, adjuvants and delivery method on integration into host DNA

A variety of factors could affect the frequency of integration of plasmid DNA vaccines into host cellular DNA, including DNA sequences within the plasmid, the expressed gene product (antigen), the formulation, delivery method, route of administration, and the type of cells exposed to the plasmid. In this report, we examined the tissue distribution and potential integration of plasmid DNA vaccines following intramuscular administration in mice and guinea pigs. We compared needle versus Biojector (needleless jet) delivery, examined the effect of aluminum phosphate adjuvants, compared the results of different plasmid DNA vaccines, and tested a gene (the human papilloma virus E7 gene) whose protein product is known to increase integration frequency in vitro. Six weeks following intramuscular injection, the vast majority of the plasmid was detected in the muscle and skin near the injection site; lower levels of plasmid were also detected in the draining lymph nodes. At early time points (1-7 days) after injection, a low level of systemic exposure could be detected. Occasionally, plasmid was detected in gonads, but it dissipated rapidly and was extrachromosomal - indicating a low risk of germline transmission. Aluminum phosphate adjuvant had no effect on the tissue distribution and did not result in a detectable increase in integration frequency. Biojector delivery, compared with needle injection, greatly increased the uptake of plasmid (particularly in skin at the injection site), but did not result in a detectable increase in integration frequency. Finally, injection of a plasmid DNA vaccine containing the human papilloma virus type 16 E7 gene, known to increase integration in vitro, did not result in detectable integration in mice. These results suggest that the risk of integration following intramuscular injection of plasmid DNA is low under a variety of experimental conditions.