Wright reaction

Wright reaction (A. E. Wright) - serological method of laboratory diagnostics of brucellosis infection.
Reaction Wright highly specific and becomes positive from the very beginning of the disease. The most high titers reaction Wright (80% and higher) is usually seen within 1-2 months. after the disease onset and continue for febrile period. Further titles reactions begin to fall, and by the end of the first year of the disease reaction Wright, as a rule, becomes negative. The emergence and accumulation of agglutinins in blood of patients with brucellosis depend on the degree of antigenic stimulation. Therefore, the most high titers of agglutinins observed in the phase of bacteremia, sharply falling in a process of attenuation of the infectious process.
Sometimes the reaction Wright remains positive to 2 or 3 or even 5 years after the disease. However, in these cases it should be borne in mind the possibility of re-infection and recurrence of the disease. In some cases of the classic brucellosis (see), confirmed by the allocation of hemoculture and positive allergic breakdown reaction Wright can be negative; this is possible if the infecting organism modified antigenically strain Brucella. Due to the similarity in antigenic structure slabopolozhitelnym results reaction Wright can be people infected with pathogens of tularemia, cholera, and some other infectious diseases, as well as in persons vaccinated against these infections. Slabopolozhitelnym reaction Wright (in dilutions of 1:50 and 1:100) are sometimes observed in healthy women during the last weeks of pregnancy. Repeated reaction arrangement Wright (monitor its dynamics) allows to differentiate a specific reaction Wright from non-specific, as increased titers indicates the presence of brucellosis infection.
A significant role in the reaction Wright plays a selection of strains for preparation of diagnosticum (dissolvine strains for this purpose is not usable), and the concentration of applied microbial suspension. In addition to the antigen source of error can be investigated serum. It should be fresh, neemalirovannuyu, transparent (without erythrocytes and other) and no indication of germination by other organisms.
When setting reactions Wright sometimes there are so-called poiglitazone zone, i.e. a negative result with low serum dilutions and definite positive result at higher dilutions; it is also possible loss of agglutination in the middle part of a series of dilutions. This phenomenon is more likely to occur at high titers of serum and necessitates the application of a long series of dilutions. The emergence of the phenomenon of the area, apparently due to the presence in the blood serum of incomplete (blocking) antibodies. The serum for research receive the usual way.
Reaction Wright always put two controls: a) monitoring of each of the investigated sera to avoid false agglutination due to the loss of proteins in the serum and b) the control antigen - one vial with any number of investigated sera - for exception of spontaneous agglutination antigen. Fiziol. the fluid used for cultivation serum and antigen should be distilled water neutral reaction (pH of 6.9 to 7.1) and prevent germination contain 0.5% carbolic acid. Reaction Wright put not less than five dilutions(1:50, 1:100, 1:200, 1:400 and 1:800) in the volume of 1 ml each. As antigen apply diagnostikum, potteromania national standard PROTIVOPOZHARNOY agglutinins serum. Before the use of diagnostikum diluted 10 times carolinianum (0,5%) saline solution. In 1 ml of diluted diagnosticum contains about 6-109 microbial cells.
Accounting reactions produce in 24 hours by comparing the degree of enlightenment in test tubes with the corresponding standard turbidity, which is prepared as follows. 4 tubes consistently pour 1, 2, 3 and 4 ml of diluted diagnosticum, then in the same order, add 3, 2 and 1 ml karbonizirovannogo physiological solution, in the last test tube and add nothing. After tilting take content of 0.5 ml of each antigen concentration and 0.5 ml karbonizirovannogo physiological solution. So get 4 tubes of the turbidity standard with varying degrees of enlightenment (75% - 3-, 50% - 2 and 25% - 1 - and the lack of enlightenment), which together with experienced tubes are placed in the thermostat at the temperature 37 deg for 24 hours, after which produce a reaction accounting. For unified accounting system currently recommend expression titles sera in international units of antibodies (ME). Diagnostic titre test serum is 50% agglutination (2+).
Enumeration titer serum on international units produce the following way. Standardized of diagnostikum with standard PROTIVOPOZHARNOY agglutinins serum containing 1000 IU of antibodies in 1 ml, gives 50% of agglutination in breeding of serum 1 : 500. Therefore, titles test serum 1 : 50, 1 : 100, 1 : 200 and so on, with the use of a standardized diagnosticum indicate that in 1 ml of test serum contains 100, 200, 400, and so on international units of antibodies. Thus, the transfer of title of the test serum on international units produced by doubling. If the diagnostic evaluation results agglutination reaction recommended the following scheme: the titre sera 1 : 50 (100 ME) - the result is doubtful, 1 : 100 (200 ME is not a very positive, 1 : 200 (400 ME) - positive, 1 : 200 and above (800 ME)is strongly positive.