I would like to discuss some of our findings that concern measurements of lysozyme. I agree with Dr. Cole that with freshly collected samples, one can get much more reliable results, but this still does not prevent two problems. Measurements of low concentrations of lysozyme on the lysoplate can be rather difficult because the lysis rings are not that sharp. The second problem concerns the day to day variation of the lysoplate which runs in the 15% range. Therefore, when you are measuring low amounts with these kinds of variables, your estimates are not very precise. Acidification of the samples allows you to determine lysozyme levels by nephelometry with anti-lysozyme serum. This method is far more accurate. I think this is what you should do when you are determining really low levels of lysozyme in saliva. The other point is that acidification does not harm the immunoglobulins. You can run unconcentrated saliva in the nephelometer with commercial standards and get determination of immunoglobulin values right away. If you consider the errors you make, in concentrating saliva samples, and in radial immunodiffusion because of different molecular sizes of IgA, I think you will have to agree with me that it is better to do the measurements by nephelometry.
KeywordsRadial Immunodiffusion Oral Flora Parotid Saliva High Molecular Weight Substance Lactoferrin Level
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