Naturally occurring, nonregressing canine oral papillomavirus infection: host immunity, virus characterization, and experimental infection.

Papillomaviruses occasionally cause severe, nonregressing or recurrent infections in their human and animal hosts. The mechanisms underlying these atypical infections are not known. Canine oral papillomavirus (COPV) typically regresses spontaneously and is an important model of mucosal human papillomavirus infections. A severe, naturally occurring, nonregressing COPV infection provided an opportunity to investigate some aspects of viral pathogenicity and host immunity. In this case, the papillomas proved refractory to surgical and medical treatments, including autogenous vaccination and vaccination with capsid (L1) virus-like particles. High levels of induced anti-L1 antibodies appeared to have no effect on the infection. The papillomas spread to oesophageal mucosa, perioral haired skin, and remote cutaneous sites. Isolation of COPV from the animal and sequencing of several regions of the viral genome showed no differences to the COPV prototype. Experimental infection of beagle dogs with this viral isolate resulted in the uncomplicated development and regression of oral warts within the usual period, indicating that the virus was not an unusual pathogenic variant. These findings support the hypothesis that the recurrent lesions seen in some human papillomavirus infections, such as recurrent laryngeal papillomatosis, are associated with specific defects in host immunity rather than variations in viral pathogenicity.

Morbilliviral epizootic in bottlenose dolphins of the Gulf of Mexico.

Morbillivirus infection was diagnosed in 35/67 bottlenose dolphins (Tursiops truncatus) from the Gulf of Mexico that stranded from October 1993 through April 1994 in Alabama, Mississippi, and Texas (USA) during periods of increased dolphin strandings in each of the 3 states. Diagnosis was based on histologic lesions, immunohistochemical demonstration of mobilliviral antigen, and detection of morbilliviral RNA by a reverse transcriptase polymerase chain reaction (RT-PCR) test performed on formalin-fixed, paraffin-embedded tissue (5 dolphins), on histologic lesions and detection of morbilliviral RNA by RT-PCR performed on formalin-fixed, paraffin-embedded tissue (1 dolphin), and on detection of morbilliviral RNA by RT-PCR performed on unfixed lung samples collected from carcasses with advanced postmortem autolysis (29 dolphins). Histologic lesions included proliferative interstitial pneumonia with syncytial cells and eosinophilic intranuclear and intracytoplasmic inclusion bodies, lymphoid depletion and syncytial cells with eosinophilic intranuclear inclusion bodies in lymph nodes, eosinophilic intracytoplasmic inclusion bodies in transitional epithelium of urinary bladder, and a syncytial cell with eosinophilic intranuclear inclusion bodies in epidermis. Concomitant pulmonary aspergillosis was diagnosed histologically in 4 dolphins. This is the 5th reported morbilliviral epizootic of aquatic mammals and the 2nd involving bottlenose dolphins in the United States.

Postmortem diagnosis of morbillivirus infection in bottlenose dolphins (Tursiops truncatus) in the Atlantic and Gulf of Mexico epizootics by polymerase chain reaction-based assay.

Lung tissue from 39 bottlenose dolphins (Tursiops truncatus) found dead off the U.S. Atlantic and Gulf of Mexico coasts from 1987 to 1994 was examined for the presence of morbillivirus using a reverse transcriptase polymerase chain reaction (RT-PCR) technique. Of the Atlantic cases examined, six of six were positive using this assay; 18 of 25 Gulf of Mexico cases with amplifiable RNA also were found to be positive, and eight additional specimens had no amplifiable RNA. The RT-PCR allowed the diagnosis of morbillivirus infection to be made from either sections of paraffin-embedded formalin-fixed material or from unfixed tissue. Conformation of diagnosis was made by subsequent hybridization of the amplified products with a dolphin morbillivirus specific probe using the Southern blot technique. Application of this method to autolyzed post-mortem tissues allows diagnoses of morbillivirus infection to be made in specimens which cannot be evaluated by histologic and immunocytochemical techniques.

Proenkephalin transgenic mice: a short promoter confers high testis expression and reduced fertility.

The regulation and possible function of the preproenkephalin gene in testis were studied in vivo in transgenic mice containing: (1) bases -193 to +210 of the human proenkephalin gene and an additional one kilobase of 3' proenkephalin flanking sequence driving expression of bacterial chloramphenicol acetyltransferase (CAT), and (2) the same promoter and flanking sequences driving expression of a rat proenkephalin cDNA. Five lines of mice, designated HEC1-5, expressed the first construct and 10, HER1-10, the second. Each HEC male and many HER males showed dramatic expression of the transgene in the testis, although much lower expression was observed in the brain and other enkephalin-producing tissues. High levels of expression in testis can thus be achieved with a very short promoter region and do not require intron A sequences previously considered necessary. Altered enkephalin expression may affect testicular function. One founder, HER8, displayed grossly abnormal testicular morphology and was completely infertile. A second founder, HER6, had low sperm motility. Two offspring from other lines also displayed subnormal fertility. These studies support a role for specific promoter sequences in testis expression and may further support a significant role for proenkephalin in testicular function.