In 1967, the success of vaccination programs, combined with the seemingly unstoppable triumph of antibiotics, prompted the US Surgeon General to declare that "it was time to close the books on ...infectious diseases." We now know that the prediction was overly optimistic and that the fight against infectious diseases is here to stay. During the last 20 yr, infectious diseases have indeed made a staggering comeback for a variety of reasons, including resistance against existing antibiotics. As a consequence, several alternatives to antibiotics are currently being considered or reconsidered. Passive immunization (i.e., the administration of more or less pathogen-specific antibodies to the patient) prior to or after exposure to the disease-causing agent is one of those alternative strategies that was almost entirely abandoned with the introduction of chemical antibiotics but that is now gaining interest again. This review will discuss the early successes and limitations of passive immunization, formerly referred to as "serum therapy," the current use of antibody administration for prophylaxis or treatment of infectious diseases in agriculture, and, finally, recent developments in the field of antibody engineering and "molecular farming" of antibodies in various expression systems. Especially the potential of producing therapeutic antibodies in crops that are routine dietary components of farm animals, such as corn and soy beans, seems to hold promise for future application in the fight against infectious diseases.
The systematics of benign and moderately pathogenic Theileria isolates from cattle and deer originating from different geographic regions was undertaken by small-subunit ribosomal RNA (SSU rRNA) gene ...nucleotide-sequence analysis. A maximum-likelihood phylogenetic tree constructed from these sequences resulted in two major divisions, each with a common ancestor. One major division branches into four relatively divergent groups, including (1) bovine Theileria sp. Type D (USA and Korea), (2) T. mutans Intona and Theileria sp. MSD (Africa), (3) T. cervi (USA), and (4) well-characterized pathogenic Theileria spp. (Africa). The other major division branches into two groups: (1) T. buffeli Warwick and T. buffeli Marula and (2) a second branch of closely related isolates with SSU rRNA gene Types B, B1, C, E, and H. Putative geographically associated diversity was noted only in the Korean bovine Theileria spp. with SSU rRNA gene types C and H and in African T. mutans Intona and Theileria sp. MSD. The current results show that the United States bovine Theileria isolates are not T. mutans because they have T. buffeli Marula (Type A) and/or Type D (species undesignated) SSU rRNA gene sequences. The taxonomic separation of T. buffeli Warwick from African T. mutans is confirmed in this study.
Recombinant antigen-based enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of
Babesia bigemina infection by using a full-length
B. bigemina rhoptry-associated ...protein 1 (rRAP-1) and the truncated C-terminal RAP-1 (rRAP-1/CT). While the rRAP-1 showed cross reactivity between
B. bigemina- and
Babesia bovis-infected bovine sera, the rRAP-1/CT was highly specific to
B. bigemina-infected bovine sera and proved useful in the detection of sequential sera collected from an experimentally infected cow during the acute and latent infection. The high yield of soluble rRAP-1/CT and its diagnostic specificity demonstrate its potential in the diagnosis of
B. bigemina infection. Its usefulness for epidemiological investigation is currently being evaluated.
The phylogenetic relationships among fourteen isolates of benign
Theileria spp. infecting cattle, elk and white-tailed deer were studied by nucleotide sequence comparisons of the variable (V4) region ...(200 nucleotides) of the small subunit ribosomal RNA gene. Included were six Korean bovine, one Japanese bovine, three North American bovine, and four North American cervine isolates. The SSU rRNA gene from each isolate was amplified, cloned, and the V4 region fragment sequenced. Seven different nucleotide sequence patterns were obtained and classified. Type A was identical to
T. buffeli SSU rRNA gene sequence (GenBank Accession No. Z15106) and was found in Korean, Japanese, and North American bovine isolates. Type B was found in bovine isolates from Korea, Japan and North America. Type C was found only in the Korean bovine isolate from Chungnam. Type D was found in a Korean and in a North American bovine isolate. Type E was found in a bovine isolate from Cheju Island of Korea and a North American cervine (elk) isolate. Types F and G were found only in North American cervine isolates (both white-tailed deer and elk) and appear to represent a species separate from the bovine isolates. The presence of several sequence types observed in most of the bovine
Theileria isolates may indicate mixed species (or subspecies) populations and/or multiple genotypes within a single species.
African Swine Fever Virus (ASFV) is a high-consequence transboundary animal pathogen that often causes hemorrhagic disease in swine with a case fatality rate close to 100%. Lack of treatment or ...vaccine for the disease makes it imperative that safe and efficacious vaccines are developed to safeguard the swine industry. In this study, we evaluated the immunogenicity of seven adenovirus-vectored novel ASFV antigens, namely A151R, B119L, B602L, EP402RΔPRR, B438L, K205R and A104R. Immunization of commercial swine with a cocktail of the recombinant adenoviruses formulated in adjuvant primed strong ASFV antigen-specific IgG responses that underwent rapid recall upon boost. Notably, most vaccinees mounted robust IgG responses against all the antigens in the cocktail. Most importantly and relevant to vaccine development, the induced antibodies recognized viral proteins from Georgia 2007/1 ASFV-infected cells by IFA and by western blot analysis. The recombinant adenovirus cocktail also induced ASFV-specific IFN-γ-secreting cells that were recalled upon boosting. Evaluation of local and systemic effects of the recombinant adenovirus cocktail post-priming and post-boosting in the immunized animals showed that the immunogen was well tolerated and no serious negative effects were observed. Taken together, these outcomes showed that the adenovirus-vectored novel ASFV antigen cocktail was capable of safely inducing strong antibody and IFN-γ+ cell responses in commercial swine. The data will be used for selection of antigens for inclusion in a multi-antigen prototype vaccine to be evaluated for protective efficacy.
Babesia isolates from an elk (Cervus elaphus canadensis) and a caribou (Rangifer tarandus caribou) with fatal infections were compared to Babesia odocoilei (Engeling isolate) from white-tailed deer ...(Odocoileus virginianus) by experimental infection, serologic, and small subunit ribosomal RNA (SSU rRNA) gene sequence analysis studies. Both the indirect fluorescent antibody test and immunoprecipitation assays demonstrated antigenic variation among the isolates. Experimental infection studies showed no clinical differences among the isolates. Nucleotide sequence analysis showed that the elk and caribou Babesia sp. isolates possessed SSU rRNA genes with identical sequences to that of B. odocoilei. A phylogenetic tree constructed from SSU rRNA gene sequences shows that B. odocoilei is most closely related to Babesia divergens, both of which branch together in the true babesia clade.
A cross-sectional study was conducted to determine individual cow seroprevalence of
Babesia bovis
in adult lactating dairy cattle of Puerto Rico (PR), to assess the associations of farm management ...factors on herd seroprevalence, and to document the species of ticks infesting cattle within these farms. Antibody activity against
B. bovis
was determined using an indirect fluorescent antibody test (IFAT). Serum samples were obtained from 2,414 adult lactating dairy cattle from 76 randomly selected commercial dairy farms. Herd seroprevalence ranged from 0 to 51% with an overall individual cow seroprevalence for
B. bovis
of 26%. Ticks were collected from animals on 7 (9%) of the 76 participating commercial dairy farms. All collected ticks (n = 87) were
Rhipicephalus (Boophilus) microplus.
Factors associated with high herd seropositivity were dairy farms with calf but not heifer raising facilities (OR = 16, 95% CI = 3.0-86), having more than 4 neighbors with cattle (OR = 17, 95% CI = 1.6-178), same producer owning more than one farm (OR = 7.2, 95% CI = 1.6-32), and use of government services to apply amitraz on cattle (OR = 5.5, 95% CI = 1.5-20).
Studies of immune responses elicited by bovine viral diarrhea virus (BVDV) vaccines have primarily focused on the characterization of neutralizing B cell and CD4
T cell epitopes. Despite the ...availability of commercial vaccines for decades, BVDV prevalence in cattle has remained largely unaffected. There is limited knowledge regarding the role of BVDV-specific CD8
T cells in immune protection, and indirect evidence suggests that they play a crucial role during BVDV infection. In this study, the presence of BVDV-specific CD8
T cells that are highly cross-reactive in cattle was demonstrated. Most importantly, novel potent IFN-γ-inducing CD8
T cell epitopes were identified from different regions of BVDV polyprotein. Eight CD8
T cell epitopes were identified from the following structural BVDV Ags: E
, E1, and E2 glycoproteins. In addition, from nonstructural BVDV Ags N
, NS2-3, NS4A-B, and NS5A-B, 20 CD8
T cell epitopes were identified. The majority of these IFN-γ-inducing CD8
T cell epitopes were found to be highly conserved among more than 200 strains from BVDV-1 and -2 genotypes. These conserved epitopes were also validated as cross-reactive because they induced high recall IFN-γ
CD8
T cell responses ex vivo in purified bovine CD8
T cells isolated from BVDV-1- and -2-immunized cattle. Altogether, 28 bovine MHC class I-binding epitopes were identified from key BVDV Ags that can elicit broadly reactive CD8
T cells against diverse BVDV strains. The data presented in this study will lay the groundwork for the development of a contemporary CD8
T cell-based BVDV vaccine capable of addressing BVDV heterogeneity more effectively than current vaccines.
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