Background and Aim: One strategy that can be used to stabilize vaccines is to convert them into a dry powder. This can protect the integrity of the active ingredients as well as vaccine antigenicity during manufacture, storage, and transport. This study highlights the potent adjuvant activity of Carbopol® when used alone to stabilize live-attenuated Newcastle disease virus (NDV) vaccines or when used in a formulation together with skimmed milk. Tolerability and potency of these formulations were compared with those obtained from other local live NDV vaccines produced locally by the Veterinary Serum and Vaccine Research Institute. Materials and Methods: We evaluated the cellular and humoral immune responses to a locally prepared, live-attenuated LaSota virus vaccine. Vaccine formulations were stabilized with Carbopol® 940 alone or in combination with skimmed milk. Results: Our results indicate that the use of Carbopol® 940 alone to stabilize a live-attenuated LaSota vaccine resulted in enhanced cellular and humoral immunity. The antibody titer was prolonged through the 6th week post-vaccination (5.0 log2). Full (100%) protection was observed in response to challenge with very virulent NDV at day 21 after vaccination; there were no clinical signs or lesions on examination. Addition of Carbopol® 940 to the live-attenuated vaccine formulation resulted in a more compact, stable, and high-quality lyophilized cake after freeze-dried lyophilization compared with that produced by stabilization with skimmed milk alone. Conclusion: Our data suggest that Carbopol® 940 may improve clinical responses to live-attenuated vaccines.

This study was conducted to assess an inactivated vaccine prepared from local field isolates of Infectious Bursal Disease (IBD) "local variant and virulent isolates" and a classical strain "bursa vacc" to improve the full control over the problem of IBD in Egypt. This experiment applied on 21 day old SPF chicks divided into six groups, the first group was vaccinated with inactivated vaccine containing (local variant isolate, classical bursa vacc strain and virulent isolate), the second group was vaccinated with inactivated vaccine containing (classical bursa vacc strain and local variant isolate), the third group was vaccinated with classical bursa vacc vaccine, and the group 4 vaccinated with local variant isolate vaccine while last two groups were left as a positive and negative control groups. The immune response of chicks was evaluated in vitro by measuring serum neutralization test (SNT) and enzyme linked immunosorbent assay (ELISA) and in vivo by challenging birds with 10 3.5 EID 50 / dose of virulent virus of infectious bursal disease virus (vvIBDV).The highest average antibody level was obtained at the 4 th week post vaccination in chicks in group 1 vaccinated with (local variant isolate, classical bursa vacc and local virulent isolate) vaccine, while the chicks in group 3 vaccinated with bursa vacc vaccine showed the lowest antibody level at the same week post vaccination using SNT and ELISA. The challenge of group 1, 2, 3 and 4 showed protection of 97.5%, 90%, 75% and 90% respectively using very virulent IBDV 28 day post vaccination with no clinical signs or lesions on examination. It was concluded that we can use an inactivated vaccine prepared from (classical strain "bursa vacc" and local variant and virulent isolates) of Infectious Bursal Disease (IBD) virus as a method for control IBD disease in Egypt. ‫ـــــــــــــــــــــــــــــــــــــــــ‬

Infectious laryngotracheitis (ILT) is a respiratory tract disease affecting chickens worldwide. The disease leads to severe production losses due to increased mortality, decreased egg production, and delayed body weight gain, causing enormous economic losses to the poultry industry. ILT is controlled through vaccination with live-modified attenuated vaccines of chicken embryo origin (CEO) and/or the tissue-culture origin (TCO). This study was conducted to develop Specific Pathogenic Free (SPF) eggadapted live attenuated ILT vaccine from the field strain Fayoum_2018 isolated from broilers in Fayoum Province, Egypt in 2018. The isolate Fayoum_2018 with accession number (MN082684) was characterized molecularly as a TCO vaccine related strain. Measurement of immunity in vaccinated chicks employing the potency test revealed that chicks vaccinated with 0.5 ml of prepared ILT vaccine exhibited ELISA with 1905 antibody titer at 2 nd-week post-vaccination, which was considered an ILT adequate immune response and increased till reach 3497 antibody titer at 6 th week post-vaccination. The current work revealed that Fayoum_2018 ILTV egg adapted live attenuated vaccine produced a satisfactory antibodies titer that was efficient in controlling the ILT field infection in Egypt.