Injection Effect of Anti-CD3 Monoclonal Antibody on Primo Vessel in Lymph Vessel of Rabbit with Lipopolysaccharide-Induced Inflammation.

Background: The primo vascular system can be viewed as a circulatory system that plays a therapeutic function in regenerating the body tissue. The anti-CD3 monoclonal antibody was used as an immunotherapeutic agent to treat the novel coronavirus infection (COVID-19). Objectives: In this study, we observed the effect of injecting lymph nodes with Foralumab, an anti- human CD3 epsilon therapeutic monoclonal antibody, on primo vessels. Methods: The structure and atomic stoichiometry of the antibody were determined by transmission electron microscopy and energy dispersive spectroscopy. Alcian blue dying solution was injected into the lymph nodes of the abdominal vena cava of rabbits, and the solution further flowed into the lymph vessels. Results: A primo vessel with primo nodes stained with Alcian blue was clearly visible in the lymph vessel. By injecting Foralumab into lymph nodes of rabbits with lipopolysaccharide-induced inflammation, the floating primo vessel in the lymph vessel appeared thicker and was distinctly visible. Conclusion: The observation of the primo vessel post-treated with Foralumab in the inflamed lymphatic system suggests the possibility of a functional role of the primo vascular circulatory system in pathophysiological conditions.

Mucina salival en pacientes obesos en relación al tratamiento de la enfermedad periodontal / Salivary mucin in obese patients in relation to the treatment of periodontal disease

Introducción: La mucina salival (Ms) modula otras proteínas salivales que participan en múltiples funciones fisiológicas de la cavidad oral. Los niveles de Ms pueden proporcionar información sobre el estado de inflamación de los tejidos periodontales. Por tanto, el objetivo del presente estudio fue evaluar los niveles Ms en pacientes obesos y no obesos, antes y después del tratamiento periodontal. Material y métodos: Un total de 60 pacientes fueron distribuidos en seis grupos, de acuerdo al índice de masa corporal (IMC) y la gravedad de la enfermedad periodontal (EP). Valores del IMC superiores a 27 correspondían a obesidad. La EP en el momento del diagnóstico se designó como leve, moderada o severa. Se recolectaron muestras de saliva completa, antes (MU-A) y después (MU-D) del tratamiento periodontal. Se evaluaron los niveles de Ms utilizando el método de Azul Alcian. Los resultados se analizaron con el Software InfoStat, mediante estadística descriptiva e inferencial. Resultados: Los valores de MU-A fueron superiores a los contenidos de MU-D (p < 0.0001). Las variaciones entre los pacientes no obesos y obesos fueron mínimas. A medida que aumentó el nivel de la EP, las variables MU-A y MU-D mostraron una disminución progresiva (p = 0.0032). Conclusiones: El nivel de Ms fue mayor en la saliva de los pacientes con EP no tratada. Ms se puede utilizar como marcador inflamatorio para la detección de EP (AU)

Introduction: Salivary mucin (sM) modulates other salivary proteins that participate in multiple physiological functions of the oral cavity. sM levels can provide information on the state of inflammation of the periodontium. Therefore, the objective of the present study was to evaluate sM levels in obese and non-obese patients, before and after periodontal treatment. Material and methods: A total of 60 patients were distributed into six groups, according to the body mass index (BMI) and the severity of the periodontal disease (PD). BMI values higher than 27 corresponded to obesity. PD at the time of diagnosis was designated as mild, moderate, or severe. Complete saliva samples were collected before (MU-B) and after (MU-A) the periodontal treatment. sM levels were evaluated using the Alcian Blue method. The results were analyzed with the InfoStat Software, using descriptive and inferential statistics. Results: MU-B values were higher than MU-A contents (p < 0.0001). Variations between non-obese and obese patients were minimal. As the level of PD increased, the variables MU-A and MU-D showed a progressive decrease (p = 0.0032). Conclusions: The level of sM was higher in the saliva of patients with untreated PD. sM can be used as an inflammatory marker for the detection of PD (AU)

Production and Characterization of Monoclonal Antibodies Against Primo Vascular System of Rat.

BACKGROUND: The primo vascular system (PVS) has been difficult to detect due to its small diameter and translucent features of the threadlike network. Thus, contrast-enhancing dyes including Alcian blue, Trypan blue and Janus green B had to be used for finding and taking out PVS from rat and mouse. OBJECTIVE: Generation of monoclonal antibodies (mAbs) against PVS of rat was intended to use as a detector for PVS and a biological tool for functional study of PVS. MATERIALS AND METHODS: Primo vessel (PV) and Primo node (PN) were isolated from organ surfaces of rat and then their proteins were isolated and injected into mouse as an immunogen. The classical traditional method was applied for production of mAbs against PVS. The various techniques, such as cell fusion, screening of hybridoma, ELISA, Western blotting (WB), immunofluorescence microscopy (IF), and limiting dilution, were used to generate mAbs against PVS. RESULTS: Among 16 mAbs generated, 4 representative mAbs were characterized with their specificities in ELISA, WB, and IF. α-rPVS-m1-1 and α-rPVS-m4-6 had strong binding affinities to PVS in both ELISA and WB but did not show specificities in IF at all. On the contrary, α-rPVS-m3-2 and α-rPVS-m3-4 almost did not respond in WB but had strong binding affinities in ELISA and specificities in IF. Two mAbs stained predominantly at extra cellular matrix and cell membrane of PVS of rat in IF, and they were able to discriminate PVS from blood vessel (BV) and lymphatic vessel (LV). CONCLUSIONS: 4 representative mAbs against PVS of rat were characterized by ELISA, WB, and IF. α-rPVS-m3-2 and α-rPVS-m3-4, which had strong specificities in IF, can be used as a tool in discriminating PVS from other similar tissues and in elucidate biological function of PVS.

Is There Volume Transmission Along Extracellular Fluid Pathways Corresponding to the Acupuncture Meridians?

Volume transmission is a new major communication signaling via extracellular fluid (interstitial fluid) pathways. It was proposed by the current authors that such pathways can explain the meridian phenomena and acupuncture effects. To investigate whether meridian-like structures exist in fish body and operate via volume transmission in extracellular fluid pathways, we injected alcian blue (AB) under anesthesia into Gephyrocharax melanocheir, which has a translucent body. The migration of AB could be seen directly and was recorded by a digital camera. The fish was then embedded and cut transversely to observe the position of tracks in three dimensions. Eight longitudinal threadlike blue tracks were recognized on the fish. The positions of these threadlike tracks were similar to meridians on the human body. Transverse sections showed that these tracks distributed to different layers of distinct subcutaneous loose connective tissues and intermuscular septa. Lymphatic vessels were sometimes associated with the extracellular blue tracks where the migration of AB occurred. Extracellular fluid pathways were found on fish through their transport of AB. These pathways operating via volume transmission appeared to be similar in positions and functions to the acupuncture meridians in Chinese medicine.

Temporal Change of Alcian Blue-Stained Primo Vascular System in Lymph Vessels of Rats.

This study aims to investigate the temporal change of a vascular system now known as the primo vascular system (PVS). We used Alcian blue (AB) dye for imaging the distribution of the PVS in lymphatic vessels. The target lymph vessels were chosen as they are easily accessible from the skin, and long-term observation is possible with intact physiological conditions due to a minimal surgical procedure. AB solution was injected into the inguinal lymph node and the target lymph vessels were located along the superficial epigastric vessels. The imaging system allowed processing for extraction of images showing changes in the AB intensity of the visualized PVS components. This newly developed procedure can be used for further study on various dynamic processes of PVS in lymph vessels.

Observation of a Flowing Duct in the Abdominal Wall by Using Nanoparticles.

The primo vascular system (PVS) is being established as a circulatory system that corresponds to acupuncture meridians. There have been two critical questions in making the PVS accepted as a novel liquid flowing system. The first one was directly to show the flow of liquid in PVS and the second one was to explain why it was not observed in the conventional histological study of animal tissues. Flow in the PVS in the abdominal cavity was previously verified by injecting Alcian blue into a primo node. However, the tracing of the dye to other subsystems of the PVS has not been done. In the current work we injected fluorescent nanoparticles (FNPs) into a primo node and traced them along a primo vessel which was inside a fat tissue in the abdominal wall. Linea alba is a white middle line in the abdominal skin of a mammal and a band of fat tissue is located in parallel to the linea alba in the parietal side of the abdominal wall of a rat. In this fat band a primo vessel runs parallel to the prominent blood vessels in the fat band and is located just inside the parietal peritoneum. About the second question on the reason why the PVS was not in conventional histological study the current work provided the answer. Histological analysis with hematoxyline and eosine, Masson's trichrome, and Toluidine blue could not discriminate the primo vessel even when we knew the location of the PVS by the trace of the FNPs. This clearly explains why the PVS is hard to observe in conventional histology: it is not a matter of resolution but the contrast. The PVS has very similar structure to the connective tissues that surround the PVS. In the current work we propose a method to find the PVS: Observation of mast cell distribution with toluidine blue staining and the PN has a high density of mast cells, while the lymph node has low density.

Finding Blue Tracks in Gephyrocharax melanocheir Fish Similar to the Locations of Acupuncture Meridians after Injecting Alcian Blue.

This study investigated whether a meridian-like distribution of Alcian blue (AB) existed after it was injected into a fish's body and suggested a new animal model for meridian study. Twenty Gephyrocharax melanocheir fish with translucent bodies were injected with AB at a point near the spinal column or the dorsal fin. Distribution of AB was observed using a digital camera and a stereomicroscope. Three or more obvious blue tracks were found: one along the spinal column, another along the posterior margin of the abdomen extending to the superior margin of the anal fin, and a third along both sides of the dorsal fin. They were similar to the locations of the governor, conceptual vessel, and urinary bladder meridians, respectively, on the human body according to the classic theory of traditional Chinese medicine. A few other blue tracks were also found, which apparently did not correspond to any known meridians. The results show that the tracks of AB share important similarities with the locations of classically described meridians and that they are mainly distributed in the interstitial space around bones and blood vessels and inside muscular interstices. This study may provide a new experimental animal model for exploring acupuncture meridians.

Protocol for Detecting the Primo Vascular System in the Lymph Ducts of Mice.

The primo vascular system (PVS), which is the proposed conduit for the acupuncture Qi, is a complex network distributed throughout an animal's body. However, even with a microscope, it is not easily detectable because of its transparency. Thus, its existence is largely unknown in current anatomy. A convincing demonstration of its existence is needed. The lymph-primo vessel (PV), which is a subsystem of the PVS, is a very effective visual demonstration of the PVS. The lymph-PVS is a mobile threadlike structure floating in lymph ducts that has been observed in rabbits, rats, and mice by several independent teams. The involved techniques are novel and rather complicated; therefore, we have already provided detailed protocols for the surgery; for the injection of the staining dye; and for the detection, extraction, and identification of the PVS in rabbits and rats. However, the mouse is one of the most important laboratory animals used for various biomedical research purposes. For the convenience of researchers who wish to initiate the PVS experiments in mice, we provide a shortened version of the protocol, despite many similarities with previously published protocols. Thus, researcher can easily obtain the samples of the lymph-PVS of mice.

Visualization of the primo vascular system afloat in a lymph duct.

Because of the potential roles of the primo vascular system (PVS) in cancer metastasis, immune function, and regeneration, understanding the molecular biology of the PVS is desirable. The current state of PVS research is comparable to that of lymph research prior to the advent of Lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). There is very little knowledge of the molecular biology of the PVS due to difficulties in identifying and isolating primo endothelial cells. Present investigations rely on the morphology and the use of differential staining procedures to identify the PVS within tissues, making detailed molecular studies all but impossible. To overcome such difficulties, one may emulate the explosive development of lymph molecular biology. For this purpose, there is a need for a reliable method to obtain PVS specimens to initiate the molecular investigation. One of the most reliable methods is to detect the primo vessels and primo nodes afloat in the lymph flow. The protocols for observation of the PVS in the large lymph ducts in the abdominal cavity and the thoracic cavity were reported earlier. These methods require a laparectomy and skillful techniques. In this work, we present a protocol to identify and harvest PVS specimens from the lymph ducts connecting the inguinal and the axillary nodes, which are located entirely in the skin. Thus, the PVS specimen is more easily obtainable. This method is a stepping-stone toward development of a system to monitor migration of cancer cells in metastasis from a breast tumor to the axillary nodes, where cancer cells use the PVS as a survival rope in hostile lymph flow.

[A comparison of methods for identifying mast cells of Cyprinus carpio].

OBJECTIVE: To compare different identifying methods of the mast cells of red crucian carp (Cyprinus carpio). METHODS: The gill filaments were taken from Cyprinus carpio infected with Edwardsiella tarda and fixed in Bouin's solution. The hematoxylin-eosin (HE), toluidine blue (TB), Alcian blue (AB), neutral red, Masson trichrome, May-Grunwald Giemsa (MGG) stainings and streptavidin-biotin complex (SABC) immunohistochemical method were used to observe the mast cells. The smears of head kidney stained by Wright-Giemsa were used as a supplementary method. RESULTS: AB and TB were desirable staining solutions for clearly displaying mast cells, and MGG staining came second. Immunohistochemical method showed the small number of tryptase-positive mast cells and a weak positive reaction. The cells in smears were dispersed and showed different developmental stages. CONCLUSION: The immunohistochemistry and the histochemical staining combined with Wright-Giemsa-stained smears are two good ways to identify the mast cells of fish.

Isolation and morphological features of primo vessels in rabbit lymph vessels.

Until now, even though intensive research has been dedicated to the primo vascular system (PVS) during these years, no statistical data on primo vessels and primo vessels in lymph flow have been available. Recently, the general morphological features of primo vessels in lymph vessels around the abdominal aorta were identified from microdissections of tissues from New Zealand White rabbits, and with Alcian blue staining, primo vessels in lymphatic vessels could be definitely identified under a digital microscope. The micro-dissected specimens in situ reveal rod-shaped nuclei stained by Acridine orange. The blue-stained nuclei, which were distributed in a broken-lined stripe, formed a tube structure of about 20 µm in diameter. The distance between the nuclei of two cells on neighboring aligned stripes, which is also the diameter of the micro tube, was measured to be about 5∼10 µm. The average length of the primo vessels was 2.4 mm, with the longest being 5.6 mm. The average size of the primo vessel was 50 µm, and the average diameters of the primo and the lymph vessels were 26.0 µm and 258.5 µm, respectively. Occasionally, without the use of Alcian blue staining, milk-white transparent primo vessels were observed floating in lymph vessels. Thus, we suggest that the PVS might also have an important function connected with the lymph system. We also expect the traditional Korean meridian system to leave its invisible world during the last thousands of years and soon enter the visible scientific world.

Visualization of the network of primo vessels and primo nodes above the pia mater of the brain and spine of rats by using Alcian blue.

By spraying and injecting Alcian blue into the lateral ventricle, we were able to visualize the network of the nerve primo vascular system above the pia mater of the brain and spine of rats. Staining these novel structures above the pia mater with 4',6-diamidino-2-phenylindole demonstrated that they coexisted in cellular and extracellular DNA forms. The cellular primo node consisted of many cells surrounded by rod-shaped nuclei while the extracellular primo node had a different morphology from that of a general cell in terms of DNA signals, showing granular DNA in a threadlike network of extracellular DNA. Also, differently from F-actin in general cells, the F-actin in the primo vessel was short and rod-shaped. Light and transmission electron microscopic images of the PN showed that the nerve primo vascular system above the pia mater of the brain and spine was a novel dynamic network, suggesting the coexistence of DNA and extracellular DNA. Based on these data, we suggest that a novel dynamic system with a certain function exists above the pia mater of the central nerve system. We also discuss the potential of this novel network system in the brain and spine as related to acupuncture meridians and neural regeneration.

Protocol for the observation of the primo vascular system in the lymph vessels of rabbits.

Molecular-level understanding of the structure and the functions of the lymphatic system has greatly enhanced the importance of this second circulation system, especially in connection with cancer metastasis and inflammation. Recently, a third circulatory system, the primo vascular system (PVS) was found in various parts of an animal's body, especially as threadlike structures floating in the lymphatic flow in lymph vessels. Although the medical significance of this emerging system will require much work in the future, at present, several important suggestions in connection with immune cells, stem cells, and cancer metastasis have already appeared. Experiments to observe the PVS in the lymph vessels near the caudal vena cava of rabbits and rats have been performed by several independent teams, but reproduction requires considerable skill and technical know-how. In this article, we provide a detailed protocol to detect the PVS inside the lymph vessels of a rabbit. Detection and isolation are the first steps in unraveling the physiological functions of the PVS, which awaits intensive research.

The low level laser therapy effect on the remodeling of bone extracellular matrix.

The low level laser therapy (LLLT) has been used as an option to accelerate the regeneration of bone tissue. In this study, both femurs of male Wistar rats (30 animals) were injured with a drill and the effect of LLLT using a laser diode (100 mW at 660 nm) in the bone matrix on the left paw measured. LLLT effect on the healing bone tissue matrix was evaluated by a combination of immunohistochemical histomorphometry, confocal immunofluorescence microscopy and isolation and characterization of glycosaminoglycans. Histomorphometric analysis showed that LLLT increased bone matrix and showing more organized. Alcian Blue and PAS staining seems to suggest differential glycosaminoglycans and glycoproteins. The data showed increased expression of chondroitin sulfate and hyaluronic acid, after reduction as the LLLT and mature bone, resembling the expression of osteonectin and biglycan. The difference in expression of siblings (DMP-1, OPN and BSP) is in accordance with the repair accelerated bone formation after the application of LLLT as compared with control. The expression of osteonectin and osteocalcin supports their role in bone mineralization protein, indicating that LLLT accelerates this process. The overall data show that LLLT bone changes dynamic array, shortening the time period involved in the bone repair.

Inhibition of basophil activation by histamine: a sensitive and reproducible model for the study of the biological activity of high dilutions.

BACKGROUND: At the beginning of this series of experiments we were looking for a model based on the use of purified commercially available compounds based on a fully described and accepted pharmacological model to study of the biological effect of high dilutions. Negative feedback induced by histamine, a major pro-inflammatory mediator, on basophils and mast cells activation via an H2 receptor me these criteria. The simplest way of measuring basophil activation in the early 1980's was the human basophil activation test (HBDT). OBJECTIVES: Our major goal was first to study the biological effect of centesimal histamine dilutions beyond the Avogadro limit, on the staining properties of human basophils activated by an allergen extract initially house dust mite, then an anti-IgE and N-formyl-Met-Leu-Phe (fMLP). Technical development over the 25 years of our work led us to replace the manual basophil counting by flow cytometry. The main advantages were automation and observer independence. Using this latter protocol our aim was to confirm the existence of this phenomenon and to check its specificity by testing, under the same conditions, inactive analogues of histamine and histamine antagonists. More recently, we developed an animal model (mouse basophils) to study the effect of histamine on histamine release. METHODS AND RESULTS: For the HBDT model basophils were obtained by sedimentation of human blood taken on EDTA and stained with Alcian blue. Results were expressed in percentage activation. Histamine dilutions tested were freshly prepared in the lab by successive centesimal dilutions and vortexing. Water controls were prepared in the same way. For the flow cytometric protocol basophils were first labeled by an anti-IgE FITC (basophil marker) and an anti-CD63 (basophil activation marker). Results were expressed in percentage of CD63 positive basophils. Another flow cytometric protocol has been developed more recently, based on basophil labeling by anti-IgE FITC (fluorescein isothiocyanate) and anti-CD203 PE (another human basophil activation marker). Results were expressed in mean fluorescence intensity of the CD203c positive population (MFI-CD203c) and an activation index calculated by an algorithm. For the mouse basophil model, histamine was measured spectrofluorimetrically. The main results obtained over 28 years of work was the demonstration of a reproducible inhibition of human basophil activation by high dilutions of histamine, the effect peaks in the range of 15-17CH. The effect was not significant when histamine was replaced by histidine (a histamine precursor) or cimetidine (histamine H2 receptor antagonist) was added to the incubation medium. These results were confirmed by flow cytometry. Using the latter technique, we also showed that 4-Methyl histamine (H2 agonist) induced a similar effect, in contrast to 1-Methyl histamine, an inactive histamine metabolite. Using the mouse model, we showed that histamine high dilutions, in the same range of dilutions, inhibited histamine release. CONCLUSIONS: Successively, using different models to study of human and murine basophil activation, we demonstrated that high dilutions of histamine, in the range of 15-17CH induce a reproducible biological effect. This phenomenon has been confirmed by a multi-center study using the HBDT model and by at least three independent laboratories by flow cytometry. The specificity of the observed effect was confirmed, versus the water controls at the same dilution level by the absence of biological activity of inactive compounds such as histidine and 1-Methyl histamine and by the reversibility of this effect in the presence of a histamine receptor H2 antagonist.

The flow path of alcian blue from the acupoint BL23 to the surface of abdominal organs.

Two hours after Alcian Blue (AB) dye was injected at the rat acupoint BL23, the abdominal cavity was examined and AB-stained threadlike structures were observed on the right abdominal cavity. Those threadlike structures were mainly distributed on the surfaces of the duodenum, colon and cecum. These threadlike structures were thin (about 50 microm) and moved freely, and were connected to corpuscles that were about 500 x 200 microm wide and also stained with AB. On analyzing the histology of the threadlike structures, rod-shaped nuclei, bundles of collagen fibers, reticulofibers, and squamous-like epithelial cells were observed. Immune cells and some sinuses were inside the threadlike structures. These characteristics describe those of Bonghan ducts. The flow paths from the acupoint to internal organs can possibly be used as paths for drug delivery.

Unique occurrence of pectin-like fibrillar cell wall deposits in xylem fibres of poplar.

Using light and electron microscopic techniques, we studied the unique occurrence of fibrillar cell wall deposits in mature xylem fibres from poplar. These cell wall deposits lined the lumen-facing side of the wall, mainly in fibres next to vessel elements. Different lines of evidence point to the pectin-like nature of these fibrillar cell wall deposits. First, specific staining by Alcian Blue 8GX, a dye with high affinity for pectic substances. Second, the strongly reduced staining of the cell wall deposits in microscopic sections treated with pectolytic enzyme. Third, concomitant staining of pits, which are known to consist mainly of pectic substances. Given the pectin-like nature of the fibrillar cell wall deposits as well as their preferred occurrence in fibres neighbouring water-conducting vessel elements, a function for the fibrillar cell wall deposits in lateral water diffusion and stem water storage is hypothesised. The hypothesis is supported by the increased abundance of these cell wall deposits in wood tissue of a drought-sensitive poplar species.

The Kruppel-like KLF4 transcription factor, a novel regulator of urokinase receptor expression, drives synthesis of this binding site in colonic crypt luminal surface epithelial cells.

The urokinase-type plasminogen activator receptor (u-PAR) plays a central role in cell migration, growth, and invasion and is regulated, in part, transcriptionally. In mice, u-PAR expression is restricted to a few tissues, one of which is the colon. We therefore screened a colon expression library for regulators of u-PAR promoter activity and identified a zinc finger protein bearing consensus sequences to the Kruppel-like family of transcription factors and showing partial homology with one of the members, KLF4. Like u-PAR, KLF4 expression is predominant in the luminal surface epithelial cells of the colonic crypt, and we hypothesized that u-PAR synthesis in these cells is directed by this transcription factor. Colon cells from KLF4 null mice showed a dramatic reduction in u-PAR protein compared with wild-type mice. Conversely, KLF4 expression in HCT116 colon cancer cells increased the amount of u-PAR protein/mRNA. Transient transfection of KLF4 with a reporter driven by 5'-deleted u-PAR promoter fragments indicated the requirement of the proximal 200 base pairs for optimal expression. Mobility-shifting experiments demonstrated binding of KLF4 to multiple regions of the u-PAR promoter (-154/-128, -105/-71, and -51/-24), and chromatin immunoprecipitation assays confirmed the binding of KLF4 to the endogenous promoter. Deletion of the -144/-123 promoter region diminished but did not eliminate the ability of KLF4 to transactivate the u-PAR promoter, suggesting cooperativity of these binding sites with respect to activation of gene expression. In conclusion, we have identified KLF4 as a novel regulator of u-PAR expression that drives the synthesis of u-PAR in the luminal surface epithelial cells of the colon.

Induced resistance to infection of lobsters Homarus americanus by Aerococcus viridans (var.) homari, the bacterium causing gaffkemia.

A vaccine composed of steam sterilized (autoclaved) cells of a virulent strain of Aerococcus viridans (var.) homari was effective in protecting lobsters Homarus americanus against gaffkemia. At 15 degrees C the heat-killed vaccines (HKV) at concentrations between 1 and 5 x 10(7) particles kg(-1) lobster body wt induced maximal protection in induction periods ranging from 7 to 11 d. Protection was substantial over the course of a 30 d post-induction trial period. Spring-caught lobsters (i.e. those more fully rehabilitated following ecdysis) gained more protection (LD50 = 1.9 x 10(4)) from the vaccination than did those caught in the late fall-early winter period (lobsters that were not yet fully recovered from ecdysis) (LD50 = 3.2 x 10(3)). The protection offered by the HK vaccine was comparable to that induced by a vaccine produced by incubating the pathogen with low concentrations (2 pg ml(-1)) of the antibiotic vancomycin. The bacterins produced by both methods exhibited similar new properties: (1) agglutination at low titres by lobster hemolymph serum, suggesting an impaired capsule layer, and (2) increased permeability to the large Alcian Blue molecule. With both vaccines, the protection may be a direct result of increased exposure to intact bacterial cell structures by the lobster defences, an exposure which otherwise would be prevented by an intact capsule.