Concerning band criteria in immunoblot
@ Lorima, duncan
In earlier years (eighties, beginning nineties) the serological test-kits in Germany and other European countries were composed mostly as the US model; the antigen spectrum in IFT, EIA, ELISA and various blots was very limited and contained the American strain B31 of Bbss, although other strains are prevalent here, with local shifts.
The majority of infections are caused by B. afzelii and B. garinii, as far as we know today. Beyond this, there is an increasing number of other human pathogen species, for example B. spielmanii, B. bavariensis, B. valaisiana, B. lusitaniae, and B. bissetti. All these species show a great genetic diversity, splitting into various strains, OspA-serotypes, genotypes.
Since 2005 there exists a German Industrial Standard (DIN 58969-44): “Medical microbiology – Diagnostics of infectious diseases in serology and molecular biology – Part 44: Immunoblot (IB); Special requirements for the detection of antibodies against Borrelia burgdorferi”. Test manufacturer are required to meet these norms.
In spite of the multiple human pathogen species and strains it is possible to use only one strain; this could also be the American strain B31. It is recommended to use a B. afzelii-strain in Germany. “An antigen preparation for IB shall either contain diagnostically relevant protein antigens of one strain of Borrelia burgdorferi or of more than one strain in order to demonstrate such a high antigenic homology to native Borrelia strains prevalent in the area of testing assuring that Borrelia infections will be detected with a high degree of sensitivity. For example, the B. afzelii strain pKo is suited as an antigen in Germany.” (DIN 58969-44)
So, many test-kits contain antigens of only one species which is not typical for the area of infection. To test against a greater number of species there is a need to prepare a greater number of antigens for the test-kit. Therefore here are used less bands, but only those which are considered highly specific
“A minimum of the following antigens shall be contained in the antigen preparation for IB: p83/p100, p58, p39, OspC, DbpA=Osp17
. Additionally, whole-cell lysate-blot shall contain p41, p30, and p21, for recombinant blot: truncated p41 (p41int). VlsE may replace this, or it may be used in addition.” (DIN 58969-44)
The minimum of tested bands are the five mentioned ones. And the test is valuated positive if two of the highly specific bands are visible.
Most test-kits capture only one species of Borrelia burgdorferi s.l., better ones the three universally known B. burgdorferi sensu stricto, B. afzelii, and B. garinii. Rarely also B. spielmanii antibodies are tested, for example: http://www.mikrogen.de/uploads/tx_oemik ... IRLBBE.pdf
But this is a matter of money, not of science.
Of course, other bands could be specific, in a less intensity, compare the table here:
http://www.laborlexikon.de/Lexikon/Tabe ... n-Blot.htm
I am sorry that I cannot provide the whole DIN-text because of copyright, one has to buy it.
http://www.named.din.de/cmd?level=tpl-a ... guageid=en
http://www.en-standard.eu/de/din-58969- ... rgdorferi/