The Role of Milk of Immunized Camel (Camelus dromedarius) in Protecting Mice Against Oral Infection
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- Category: Biological Sciences
- Published: Wednesday, 09 May 2012 03:00
- Written by Iqbal Qatananni
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Abstract
The Role of Milk of Immunized Camel (Camelus dromedarius) in Protecting Mice Against Oral Infection with Salmonella typhimurium
Iqbal Qatananni
Camel immune system produces a unique type of antibodies in addition to their conventional ones. The non-conventional antibodies are devoid of the light chain and the first constant heavy domain but are still fully functional. These heavy chain antibodies (HCAbs) are small and have the capability to resist heat and extreme pH that enable them to retain their activity as they pass through the gastrointestinal tract, rendering them convenient for in oral immunotherapy. This study investigated the protective effect of antibodies secreted in camel milk against Salmonella typhimurium (S. typhimurium) and its potential use in oral immunotherapy to protect BALB/c mice against salmonellosis. Skimmed milk of Salmonella immunized camel was decaseined by renneting and concentrated as 2.5 x and 7.5 x then were used in 2 separate experiments with the goal of testing the effect of antibody dose. Mice infected with the lethal dose of S. typhimurium showed a mean survival days (MSD) of 6.5 ± 6.7 and 2.2 ± 0.98 days for two experiments at 2.5x and 7.5x milk concentratessss respectively. Using the 2.5x concentrated camel milk the MSD were increased to 12.2 ± 6.3 days when the bacteria and milk antibodies were mixed before inoculation (premix). Moreover, a 7.5 milk concentrate increased the MSD to 13.2 ± 2.0 days which was achieved when the milk containing antibodies was given to mice at the time of bacterial inoculation (simultaneously). The dissemination of bacteria to internal organs through the blood was successively reduced in treated mice. The mean colony forming units (CFU) in the blood of infected mice was 4.0×103±5.5×103 CFU in the first day of infection which was completely absent in a premix treated mice (2.5x). However, 66.7 ± 163.3 CFU were found in the blood of mice treated with 7.5x antibody concentrate and infected, simultaneously. Livers and spleens were highly infested with Salmonella at the time of mice death for experiment 1 (1.5×106±1.2×106CFU for both organs). Such numbers were reduced to 1.7×105±3.7×105 CFU for both organs in a premix treated group. In experiment 2 the number of CFU in the livers was reduced from 1.3×106 ± 5.8×105 of infected untreated mice to 1.3×104 ± 2.9×104 in group treated and infected simultaneously. In the same group the treatment reduced the number of CFU in spleens from 1×106±8.1×105 in infected untreated to 4.7×103 ± 1.1×104 CFU. This study proved for the first time the ability of orally administered camel antibodies derived from milk to prevent S. typhimurium infection and reduces dissemination in BALB/c mice. Furthermore, our result showed that the success of passive immunization depends on many factor such the dose and the time between exposure and the start of treatment. Elucidation of the antibody isotype responsible for the protection of mice needs further investigations.