Acute stress promotes post-injury brain regeneration in fish.

The central nervous system and the immune system, the two major players in homeostasis, operate in the ongoing bidirectional interaction. Stress is the third player that exerts strong effect on these two 'supersystems'; yet, its impact is studied much less. In this work employing carp model, we studied the influence of preliminary stress on neural and immune networks involved in post-injury brain regeneration. The relevant in vivo models of air-exposure stress and precisely directed cerebellum injury have been developed. Neuronal regeneration was evaluated by using specific tracers of cell proliferation and differentiation. Involvement of immune networks was accessed by monitoring the expression of selected T cells markers. Contrast difference between acute and chronic stress manifested in the fact that chronically stressed fish did not survive the brain injury. Neuronal regeneration appeared as a biphasic process whereas involvement of immune system proceeded as a monophasic route. In stressed fish, immune response was fast and accompanied or even preceded neuronal regeneration. In unstressed subjects, immune response took place on the second phase of neuronal regeneration. These findings imply an intrinsic regulatory impact of acute stress on neuronal and immune factors involved in post-injury brain regeneration. Stress activates both neuronal and immune defense mechanisms and thus contributes to faster regeneration. In this context, paradoxically, acute preliminary stress might be considered a distinct asset in speeding up the following post-injury brain regeneration.

Application of ultrasound in vaccination against goldfish ulcer disease: a pilot study.

Antigenicity and immunogenicity of Aeromonas salmonicida soluble A-layer protein (AP) and formalin-killed bacterin were assessed in goldfish (Carassius auratus L.) by applying ultrasound-immersion (USI) and injection (Inj) routes. No adjuvant was used in USI while IFA was used in Inj. The USI treated fish did not produce detectable acquired antibodies; however, this group stimulated by AP proved to be best protected against challenge infection with a homologous virulent strain of A. salmonicida. The results reveal the asset of USI technique in fish vaccination and indicate the option of designing a pure AP-based ballast-free vaccine.

Vertical and horizontal transmission of tilapia larvae encephalitis virus: the bad and the ugly.

Impairment of innate immunity in tilapia larvae after vertical and horizontal infection with the newly characterized tilapia larvae encephalitis virus (TLEV) was accessed by evaluation of cell-mediated reactive oxygen species (ROS) production in affected fish with the use of horseradish peroxidase-amplified luminol-dependent chemiluminescence assay. The priming in-vivo infection with TLEV resulted in downregulation of ROS response in both vertically- and horizontally-infected fish; this suppression was further exacerbated by specific in-vitro booster infection with the same virus. Application of Ca ionophore and phorbol myristate acetate as alternative nonspecific boosters enabled restoration of ROS release in vertically-infected but not in horizontally-infected larvae. The results indicate severe TLEV-imposed phagocyte dysfunction in affected larvae. The difference in restoration potential of ROS production after vertical and horizontal virus transmission is interpreted in the frame of principal distinctions between the two modes.

Viral encephalitis of tilapia larvae: primary characterization of a novel herpes-like virus.

We report here an outbreak of an acute disease that caused high mortality rate in laboratory-reared tilapia larvae. The disease was initially observed in inbred gynogenetic line of blue tilapia larvae (Oreochromis aureus) and could be transmitted to larvae of other tilapia species. Based on the clinical manifestation (a whirling syndrome), we refer to the disease as viral encephalitis of tilapia larvae. The disease-associated DNA virus is described and accordingly designated tilapia larvae encephalitis virus (TLEV). A primary morphological, biophysical and molecular characterization of TLEV is presented. By virtue of these properties, the newly discovered virus is a herpes-like virus. Phylogenetic analysis, albeit limited, confirms this assumption and places TLEV within the family of Herpesviridae and distantly from the families Alloherpesviridae and Iridoviridae. By using PCR with virus-specific primers, diseased larvae and adult TLEV carriers were also identified in tilapia delivered from external hatcheries.

Determinants of pathology in light-irradiated cells.

This work is devoted to further evaluation of pathological states in light-irradiated cells in terms of relationship between the level of reactive oxygen species (ROS) and polymorphonuclear neutrophil (PMN) count. Human leukocytes were isolated from 34 donors exhibiting flu-like symptoms, irradiated with a nonlaser blue light (2 and 5 mW cm(-2)) and examined for ROS production by a chemiluminescence (CL) assay. The level of ROS was measured as a basal chemiluminescence before (BCL0) and after (BCL) irradiation. In our preceding study (Sinyakov, M. et al. [2007] Photomed. Laser Surg.25, 257-263), PMN-oriented group analysis was applied to a data set divided into light-resistant and light-sensitive points, and cell responsiveness to light was suggested for prognostic evaluation of pathology. In the present work, BCL-oriented analysis was performed on the whole data set to evaluate the individual contribution of every point. BCL level and PMN count were confirmed to be independent variables. Sign-specific delta (DEL) values (DEL = BCL - BCL0) were assessed in relation to respective levels of BCL, BCL0 and PMN counts. DEL and BCL0 were found to be reliable photochemical indices of pathology. Taken together, the results obtained from group and individual analyses provide a novel outlook on the dynamics of pathological development and indicate a promising potential of the assay as a fast discriminator between the nonpathological state and different levels of pathology.

Chemiluminescent analysis of light-irradiated leukocytes as a diagnostic tool for fast identification of pathological states.

OBJECTIVE: Reactive oxygen species (ROS), mainly produced by polymorphonuclear neutrophils (PMN), are a significant part of host defense in pathologic states. We attempted to relate numbers of PMN and ROS generated within PMN to develop an alternative photochemical approach for evaluation of the potential of these cells to resist the development of inflammatory pathology. BACKGROUND DATA: Lack of sensitivity to light has been reported in healthy cells, while sensitivity to light characterizes cell pathology. METHODS: Human leukocytes from 34 donors were isolated and irradiated with a non-laser blue light (2 and 5 mW/cm(2) for 2 minutes), and a luminol-dependent chemiluminescence assay that reflects intracellular production of ROS was applied thereafter. The levels of basal chemiluminescence (BCL) were related to respective numbers of PMN. RESULTS: A light-insensitive cluster was discovered within the total sample and was considered to be a discrete nonpathological group. Following elimination of this group, the rest of the sample was divided into three well-defined light-sensitive groups, which were attributed to various pathological states, and differed in PMN numbers and BCL counts. Within these groups the two traits were interrelated, and each PMN range was associated with a respective level of intracellular ROS. CONCLUSIONS: Leukocyte responsiveness to light can be used for discrimination between pathological and nonpathological states and prognostic evaluation of pathological development. Patients exhibiting similar clinical symptoms could be divided into separate groups with potentially different outcomes. A novel definition of nonpathological states as well as the mechanism underlying the bell-shaped curve that delineates the relationship between PMN number and intracellular ROS is suggested in pathological states.

Nano- and microparticles as adjuvants in vaccine design: success and failure is related to host natural antibodies.

Bovine serum albumin (BSA) and the surface A-layer protein (AP) of an atypical strain of fish bacterial pathogen Aeromonas salmonicida were covalently linked with polymeric nano- and microparticles, and antigenicity of the resulted conjugates was compared in mice and goldfish. Distinct albeit different levels of natural BSA and AP antibodies were present in both animal species. Significant stimulation of the anti-AP antibody response in mice strikingly contrasted to unresponsiveness or even suppression in fish. The results negatively correlate with the levels of respective natural antibodies in the host and are discussed in context of problems related to fish vaccination. The work reinforces the instructive role of natural antibodies in adaptive immune response.

Experimental handling stress as infection-facilitating factor for the goldfish ulcerative disease.

Experimental handling stress (EHS) was applied to clinically asymptomatic farmed goldfish (Carassius auratus L.). EHS affected the gills and skin integrity of the fish and was accompanied by increased levels of plasma glucose, cortisol and interleukin-10 (IL-10). EHS application was followed by highly significant enhancement of the rate of infection with a virulent Aeromonas salmonicida isolate. Cumulative ulceration at the initial phase of the ensuing goldfish ulcerative disease (GUD) evidenced a facilitating role of EHS in the onset of GUD. Host susceptibility to the pathogen increased from 40% in unstressed fish to 90% in the stressed fish. A. salmonicida could be reisolated from the early-stage skin lesions only, whereas opportunistic strains, other than A. salmonicida (A. sobria and A. hydrophila), were recovered from progressive-stage ulcers. The implication of these findings in fish aquaculture is discussed.

Platelet-associated antibodies mediate protective autoimmune response in schizophrenia.

The peripheral blood platelets of schizophrenic patients were isolated, and the level of the platelet-associated antibodies (SPAA) was correlated with the rating scores of discrete schizophrenic symptom clusters evaluated with the Brief Psychiatric Rating Scale. Irrespective of medication and gender, symptom-dependent correlations were established between the SPAA levels and the relevant psychometric scores. The results indicate a heterogeneous origin of schizophrenia and imply the involvement of an autoimmune arm as a predominantly protective immune response.

Natural antibodies and their significance in active immunization and protection against a defined pathogen in fish.

Natural antibody activity against Aeromonas salmonicida extracellular A-layer protein (A-protein) showed large individual variations in a farmed group of 101 goldfish (Carassius auratus L.). Statistical analyses of these variations led us to divide this group into homogeneous high and low naturally active (HNA and LNA) subgroups. The HNA fish were largely protected against experimental infection with a virulent atypical A. salmonicida strain, while 100% morbidity was recorded in the LNA group. In the course of active immunization with a particulate form of A-protein, a significant antibody response was exhibited by the LNA group only. Significance and implication of these results in vaccination practice are discussed.