Genomics and Applied Biology 2016, Vol.7, No.4, 1-8
2
configuration (Lutz et al., 2007). The role of Nab involves provision of a barrier to infection by providing a
pre-existing antibody reactivity thus allowing animals to recognize the invading pathogen prior to adaptive
immunity (Chou et al., 2008).
Most of Nab binds pathogen-associated molecular patterns (PAMPs) that are conserved along different genera and
this serve as targets for identification of microbes by the innate immune system (Kohler et al., 2003). Important
PAMPS are lipopolysaccharide (LPS) present on gram-negative entero-bacteria, such as E. coli or Salmonella
spp.; lipoteichoic acid (LTA) present on gram-positive bacteria, such as S. aureus; or peptidoglycan (PGN) present
on gram-negative and gram-positive bacteria (Ploegaert et al., 2010). Besides the PAMPs, Nab do bind many
solubilized extracts of liver, kidneys, stomach, muscle, thymus, lungs, nuclear, tumors and red blood cells
components prepared in the presence of Sodium dodecyl sulfate (SDS) (Madi et al., 2010).
Natural antibodies can be categorized into two classes: the first class are directed against self antigens, are called
natural auto antibodies (Naab) or cryptic, hidden, masked, latent or silent Nab (Cheng and Chamley, 2008;
Khobondo et al., 2015a). They inactivate cytokines, clear obsolete or damaged cells and metabolic waste and are
believed to play part in surveillance or homeostasis maintenance (Lutz et al., 2007). The second class are the overt
Nabs, which are readily detected in unfractionated untreated normal sera. These Nabs bind antigen that an
individual has never encountered before such as keyhole limpet hemocyanin (Bergstra et al., 2010).The Keyhole
limphet hemocyanin is a protein antigen from megathura cranulata, a deep sea organism that is assumed never to
have had prior encounter with terrestrial animals. Therefore any immune response against it will be innate in
nature (Parmentier et al., 2004). Nab can thus be tested as a parameter for immune response and genetic variation
estimation.
It is a prerequisite that, for a parameter of disease resistance to be acceptable in genetic studies, it should be
variable to justify selection. Furthermore, there is no standard biological molecule so far to measure disease
resistance or tolerance. Several disease parameters have been investigated to measure immunity and disease
resistance. These include cytokines; tumor necrosis factor (TNF) and interferon (IFN), cellular components (eg B,
T and NK cells) and Reactive Oxygen Sulphite (ROS) production by phagocytic cells in blood and milk from
healthy cows (Ploegaert et al., 2010). A study by Ploegaert et al. (2010) reported high repeatability and significant
variation of cytokines as well as reasonable repeatability of Nabs and milk components of cows. Other than
variation, a trait should be repeatable to be sampled once under the same environmental conditions. Repeatability
of a parameter is important to assess whether a single test on single sample collection is adequate to make
inferences or reproducible thus reducing the cost of taking repeated measures. The value of repeatability can be
useful in estimating the upper limit of heritability.
Overt Nabs could be the antibodies of choice for exploring disease resistance parameter and future association
with diseases in IC and other animals. Therefore the objectives of this study were a) to determine the presence and
variation of Nab isotypes IgA, IgG and IgM binding KLH in clinically healthy indigenous chicken (IC) and b) to
estimate repeatability of IgA, IgG and IgM Nab titres binding KLH of IC sampled four times in three weeks. The
research findings give useful insight into genetic basis of Nabs and prospects of selective breeding for disease
resistance or association in IC.
2 Material and Methods
2.1 Experimental population
The base population of chicken used in this study were established through collection of chicken and eggs from
unselected, random mating population of IC from the rural farmers of Kakamega, Bondo, West Pokot, Narok,
TaitaTaveta, Lamu and Bomet counties in Kenya thus called ecotypes. The counties were chosen because there
has been minimum genetic dilution of the IC by introduction of exotic chicken. From these chicken and eggs, a
population of IC was established on station at Egerton University.
From the established population, eggs were simultaneously incubated but separated according to ecotype within
