Variable major proteins of Borrelia hermsii. Epitope mapping and partial sequence analysis of CNBr peptides.

The variable major proteins (VMP) of serotypes 7 and 21 of the relapsing fever agent Borrelia hermsii were isolated by detergent extraction and high performance liquid chromatography. Cyanogen bromide (CNBr) digestion of the isolated VMP yielded two peptides of apparent molecular weights 20,000 (20 K) and 16 K from VMP7, and three peptides of 14.5, 14, and 7 K mol wt from VMP21. Serotype-specific monoclonal antibodies bound in Western blots to one of each of the two or three CNBr fragments from the homologous VMP. A single monoclonal antibody bound to the whole cells, the isolated VMP, and a CNBr fragment of both serotype 7 and serotype 21. (This crossreactive antibody did not, however, bind to any of four other serotypes examined.) Regional conservation of structure between VMP7 and VMP21 was also shown by amino acid sequence analysis of the N-termini of the five CNBr fragments. One pair of aligned fragments from VMP7 and VMP21 had 80% amino acid homology in sequence; a second pair had 40% homology. The partial amino acid homologies between two VMP suggest that these proteins are products of members of a polygene family.

Posttranslational processing of endogenous and of baculovirus-expressed human gastrin-releasing peptide precursor.

The 27-amino-acid gastrin-releasing peptide (GRP1-27) is a neuropeptide and growth factor that is synthesized by various neural and neuroendocrine cells. The major pro-GRP hormone (isoform I) contains both GRP1-27 and a novel C-terminal extension peptide termed pro-GRP31-125. In order to define potentially active neuropeptides that could be generated from this novel protein domain, we analyzed the posttranslational processing of endogenous human pro-GRP1-125 in a small-cell lung cancer cell line. Because such studies are much easier in an overexpression system, we investigated at the same time the posttranslational processing of baculovirus-expressed human pro-GRP1-125 in an insect ovary cell line. In the small-cell lung cancer cell line, GRP1-27 was cleaved as expected from the endogenous prohormone at a pair of basic amino acids (29 and 30) and alpha-amidated at its C-terminal methionine; however, a number of novel peptides were generated by additional cleavages in the pro-GRP31-125 domain. In the insect ovary cell line, GRP1-27 was cleaved from the expressed prohormone by a different mechanism, as were a number of other peptides that appeared to be similar in size to those produced by the human neuroendocrine tumor cell line. These data show for the first time that an insect ovary cell line that is widely used to overexpress proteins can process a human neuropeptide precursor. They also reveal the existence of novel pro-GRP-derived peptides that are candidates for biologically active ligands.

Incidence and outcome of traumatic brain injury in an urban area in Western Europe over 10 years.

INTRODUCTION: Valid epidemiological data on incidence and outcome of traumatic brain injury (TBI) show great variability. A study on incidence, severity and outcome of TBI was conducted in an urban area of one million inhabitants. MATERIALS AND METHODS: 130,000 prehospital emergencies were screened for TBI. INCLUSION CRITERIA: Glasgow Coma Scale (GCS) score or=2 with confirmed TBI via appropriate diagnostics. RESULTS: Annual incidence was 7.3/100,000. Overall mortality rate was 45.8%: 182 (28%) were prehospital deaths, 116 (17.8%) patients died in hospital. Two hundred and fourteen of 352 (60.8%) surviving patients were sufficiently rehabilitated at discharge [Glasgow Outcome Scale (GOS) score = 1], but 138 patients (39.2%) survived with persisting deficits. GOS was associated with initial GCS and AIS(head). CONCLUSION: The incidence of TBI was lower compared to the literature. The overall mortality was high, especially prehospital and early in-hospital mortality rates.

N-terminal amino acid sequence of the histidine-rich protein from Plasmodium lophurae.

We have determined the N-terminal amino acid sequence of the first 25 amino acids of the histidine-rich protein (HisRP) isolated from granules of the avian malaria parasite Plasmodium lophurae. The protein was purified from cytoplasmic granules and shown to be 65.2 mol % histidine, close to the previously described value of 73 mol % histidine (Kilejian (1974) J. Biol. Chem. 249, 4650-4655). Ten of the first 25 residues were histidine, five of which formed the sequence His-His-His-His-His (positions 14-18). Also notable was the presence of eight acidic residues within the N-terminal 25 residues. HisRP contained no detectable carbohydrate. When the HisRP was biosynthetically labeled in cultured infected erythrocytes, incorporation of [3H]His greatly exceeded [3H]Ile. Labeled HisRP was not solubilized with 1% w/v Triton X-100 but could be solubilized with greater than or equal to 1% w/v sodium dodecyl sulfate. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the [3H]His labeled protein migrated as a doublet (Mr 53 000 and 50 000). Only one of these bands (Mr 53 000) comigrated with the Coomassie Blue stained protein isolated by the acid-extraction procedure from purified granules. The amino acid composition of HisRP and presence of five contiguous histidine residues in the sequence studied here suggests that other sequences of several contiguous histidine residues must exist in this molecule.

Decay accelerating factor (DAF) peptide sequences share homology with a consensus sequence found in the superfamily of structurally related complement proteins and other proteins including haptoglobin, factor XIII, beta 2-glycoprotein I, and the IL-2 receptor.

Amino acid sequence data derived from tryptic peptides of the decay accelerating factor indicate that this complement regulatory protein contains a sequence with homology to the superfamily of structurally related complement proteins, including the C4 binding protein, factor H, complement receptor type 1, complement receptor type 2, Ba, C1r, and to their non-complement relatives, including beta 2-glycoprotein I, factor XIIIb, the alpha 1 chain of haptoglobin, and the interleukin 2 receptor. Identifying DAF as a member of the superfamily of structurally related complement proteins provides evidence that DAF may contain a functionally important C4b and C3b binding domain.

Base deficit development and its prognostic significance in posttrauma critical illness: an analysis by the trauma registry of the Deutsche Gesellschaft für unfallchirurgie.

This prospective, multi-center, observational study of 2069 multiple trauma patients evaluated the prognostic significance of the posttrauma base deficit (BD) on hospital and intensive care unit (ICU) admission to hemodynamic changes, volume and transfusion requirements, lactate and coagulation, as well as mortality. Furthermore, the importance of the BD development throughout a patient's course of critical illness from the time of injury to ICU admission is analyzed as a prognostic factor for fatal outcome. The data were obtained by the trauma registry of the 'Deutsche Gesellschaft für Unfallchirurgie.' The patients were subdivided into five categories of increasing BD values on hospital and ICU admission: Category I, BD < or = -2; Category II, -2 < BD < or = 2; Category III, 2 < BD < or = 6; Category IV, 6 < BD < or = 10; and Category V, BD > 10. A statistical analysis was performed by means of the ANOVA and chi-square tests. In 1264 (61.1%) of 2069 multiple trauma patients (age 39 +/- 19 years, 70.0% males, injury severity score 22 +/- 13, 18.6% mortality), the BD was documented on hospital and in 1536 (74.2%) patients on ICU admission. At both points in time, an increase in the BD category was associated with a significant decrease in systolic blood pressure and prothrombin time as well as increases in heart rate, lactate level and mortality (P < 0.0001). Also transfusion requirements (Category I: 4.5 +/- 7.7 and Category V: 13.7 +/- 13.0 packed red blood cells) increased significantly on hospital admission (P < 0.0001) with a worsening in the BD category. Mortality increased significantly (P < 0.0001) with a worsening of BD from hospital to ICU admission (from a mortality of 13% in patients with a hospital and an ICU admission BD of <6 to 45% in patients with a hospital and an ICU admission BD of >6). These data show that the base deficit is an early available important indicator to identify trauma patients with hemodynamic instability, high transfusion requirements, metabolic and coagulatory decompensation, as well as a high probability of death. The base deficit development may help to guide an early and aggressive therapy for the trauma/hemorrhage induced tissue hypoxia.

A pig hemorrhagic shock model: oxygen debt and metabolic acidemia as indicators of severity.

"Uncontrolled bleeding," "a controlled prefixed bleeding volume," or "controlled decrements in blood pressure" are traditional models of experimental hemorrhagic shock. They are influenced by compensatory mechanisms and do not adequately reflect the severity of the cellular insult as a major target for therapeutic strategies. The aim of this study was to develop an animal model that uses oxygen debt (OD) and metabolic acidemia as indicators of hemorrhage severity. Twenty-five female pigs (mean weight: 23.8 kg) were anesthesized and randomized to 1 of 5 groups of increasing OD (<50 through >120 mL/kg). The predetermined OD was accrued by hemorrhage uniformly over 60 min and followed by retransfusion. The animals were allowed to recover under anesthesia for 200 min and were then observed for 3 days. The extent of metabolic derangements were quantified by arterial base excess (BE) and plasma lactate (LAC) measurements. OD, BE, and LAC were shown to be superior as predictors of outcome in comparison with traditional variables ("bleeding volume," "blood pressure," "cardiac output") in correlation and regression. Of the analyzed predictors of outcome, BE and LAC showed the highest correlation to levels of OD (r = -0.78, 0.8 respectively; P < 0.0001), and regression models were developed. The LD50 for OD was 95.0 mL/kg, for BE -15.3 mmol/L and for LAC 7.7 mmol/L. By using the developed regression models, it is possible to estimate accurately the actual level of OD from BE and LAC values obtained during hemorrhagic shock. OD, BE, and LAC appear to be optimal indicators of severity for a pig hemorrhagic shock model.

The incidence and outcome of severe brain trauma - Design and first results of an epidemiological study in an urban area.

Epidemiological data on the incidence, the prehospital and hospital care and the outcome of traumatic brain injury in Germany are scarce. It is therefore difficult to estimate the importance of this injury with respect to magnitude as well as effectiveness and efficiency of therapeutic concepts. We therefore planned a study that was supposed to provide population based epidemiological data in the field of severe brain trauma from the site of the accident until discharge from hospital.All 90.000 prehospital emergencies that were cared for by emergency physicians in Cologne from January 1990 until December 1996 were screened for identification of severe brain trauma. Their clinical course was reviewed using standard records and patients were included if they had their accident within the city of Cologne and fullfilled the final inclusion criteria of GCS ≤ 8 or AISHead ≥ 3. 650 eligible patients were identified of whom 530 had complete datasets (follow-up 80 %). Univariate statistical analysis was performed for all relevant variables. The main study endpoints were incidence and outcome of severe brain trauma.The annual incidence of severe brain trauma in Cologne (1 mio. inhabitants) was 93. The average age was 39 years and 71 % of the patients were male. The average prehospital GCS was 6.8, the average prehospital Trauma Score was 8.3 points. 49 % of the study population suffered from multiple injuries. The overall mortality rate was 46,6 %. 60 % of deaths occurred within the prehospital setting.The incidence of severe brain trauma in Cologne in this study was significantly lower compared to what could be expected from the literature. The overall mortality was high, especially the high prehospital death rate is striking.

[Compartment syndrome: a complication of lithotomy position]. / Das Kompartmentsyndrom: eine Komplikation der Steinschnittlagerung.

Urological operations are commonly performed in the lithotomy position. A rare, but serious, complication is the compartment syndrome, which can result in neurovascular damage and permanent disability or limb loss. We describe two cases of compartment syndrome. One arose after transurethral resection of the prostate, and the other after an operation to change a transsexual patient from man to woman. The literature is reviewed, and the causes of the syndrome and possible ways of preventing serious consequences to the patients affected are discussed.

Impact of fluid therapy on apoptosis and organ injury during haemorrhagic shock in an oxygen-debt-controlled pig model.

INTRODUCTION: Apoptosis, or programmed cell death, seems to play a role in the physiology of shock. The influence of fluid resuscitation on the occurrence of apoptosis during haemorrhage is still unclear. Using an experimental randomised study, the goal of this investigation was to find a relation between different frequently used resuscitation fluids and evidence of apoptosis. MATERIALS AND METHODS: Sixty female pigs with a mean body weight of 20 kg were randomised into six groups, each receiving a different resuscitation fluid therapy: malated Ringer, lactated Ringer, hypertonic saline, hypertonic saline solution/Dextran 60, carbonate/gelatine and a sham group (no shock, no resuscitation). A haemorrhagic shock with a predefined oxygen debt with high mortality expected was induced for a period of 60 min. Then, the resuscitation fluid therapy within each group was initiated. At the beginning, after 1 h of shock and 1 and 2 h after resuscitation, biopsies from the liver were taken, as one of the most important metabolism organs of shock. Three hours after the beginning of the resuscitation period, the animals were allowed to recover under observation for 3 days. At the end of this period, a state of narcosis was induced and another liver biopsy was taken. Finally, the animals were sacrificed and samples were taken from the liver, kidney, heart and hippocampus. The TUNEL method was used for identifying apoptosis. Impairment of liver function was indicated by the measurement of transaminase levels. RESULTS: There was no observed difference in the rate of apoptosis in all groups and a low number of apoptotic cells were found in all the organs sampled. The sham group also showed a low count of apoptosis. The hypoxia-sensitive neurons within the hippocampus did not show any signs of apoptosis. The high oxygen debt during haemorrhage led to a high mortality. The non-treated animals died very quickly, as an indicator for severe shock. Animals treated with hypertonic saline showed a significant increase in aspartate transaminase (AST) plasma levels on the first day after shock. CONCLUSION: The different resuscitation fluids used in the treatment of haemorrhagic shock in this experimental model showed no evidence of a different apoptosis rate in the end organs.

Thirty years of anti-mediator treatment in sepsis and septic shock--what have we learned?

Sepsis, the systemic response (specific and non-specific) of the body to an infection, is an increasing clinical problem. During the last 30 years, nearly 50 clinical trials involving more than 10,000 patients have failed to demonstrate improvement of patients' outcome with different "anti-mediator" strategies. The wrong conceptional approaches to interact with the complex mediator network and flaws in study design and conduct are the main reasons for this disappointing situation. We learned, however, that the systemic host response is more than persistent uncontrolled inflammation; it is also a stimulation of the counter regulatory network. Although it is important to analyse the complex picture, we have now reached a point where more sophisticated strategies for describing complexity and novel attempts for synthesis are needed. Along this line, improved study designs (decrease of "signal-to-noise ratio") are mandatory. In addition, secondary preventive strategies are emphasised.

[Systematic literature searches for clinical guideline development in the field of out-of-hospital and early in-hospital care of multiply injured patients]. / Systematische Literatursuchen in der Erstellung klinischer Leitlinien am Beispiel der prä- und frühklinischen Versorgung polytraumatisierter Patienten.

QUESTION: To what extent does the scientific literature have an impact on current clinical practice guidelines (CPGs) in trauma surgery? METHODS: We searched for CPGs on the initial management of multiply injured patients and assessed the quality of literature search and appraisal within these CPGs. Secondly, we compiled a list of all medical journal with relevance to prehospital trauma care. Lastly, we performed a hand search for randomised controlled trials (RCTs) in some of the German not in Medline indexed traumatological journals. RESULTS: We identified 22 CPGs of varying methodological quality. The American guidelines scored highest. Only 21 of the 38 journals (55%) in the field of prehospital trauma surgery were indexed in Medline, while 6 were covered only by Embase and 11 were indexed in neither of both databases. Hand searching four non-indexed German journals identified nearly 200 RCTs. CONCLUSION: Information flow between clinical research and CPG development remains difficult. Thoroughly performed literature searches have an important role in CPG development.

[Technology assessment of ultrasound in acute diagnosis of blunt abdominal trauma]. / Technologiebewertung des Ultraschalls in der Akutdiagnostik des stumpfen Bauchtraumas.

In this article a systematic technology assessment was used for ultrasound in blunt abdominal trauma. We found sonography to be a simple, fast and complication-free method with high sensitivity and specificity. Ruptures of the small bowel seemed to be extremely difficult to detect, especially in the early phase after blunt abdominal trauma. No basic definitions of significant free fluid and maximal limit for non-operative treatment are found in the international literature. Only the combination of prognostic factors such as mechanism of the accident, clinical examination, and the intuition of the surgeon leads to a decision.

[Predicting the outcome in severe injuries: an analysis of 2069 patients from the trauma register of the German Society of Traumatology (DGU)]. / Prognoseabschätzung des Schwerverletzten--Eine Analyse von 2069 Patienten des Traumaregisters der DGU.

UNLABELLED: On hospital admission numerous variables are documented from multiple trauma patients. The value of these variables to predict outcome are discussed controversially. The aim was the ability to initially determine the probability of death of multiple trauma patients. Thus, a multivariate probability model was developed based on data obtained from the trauma registry of the Deutsche Gesellschaft für Unfallchirurgie (DGU). PATIENTS AND METHODS: On hospital admission the DGU trauma registry collects more than 30 variables prospectively. In the first step of analysis those variables were selected, that were assumed to be clinical predictors for outcome from literature. In a second step a univariate analysis of these variables was performed. For all primary variables with univariate significance in outcome prediction a multivariate logistic regression was performed in the third step and a multivariate prognostic model was developed. RESULTS: 2069 patients from 20 hospitals were prospectively included in the trauma registry from 01.01.1993-31.12.1997 (age 39 +/- 19 years; 70.0% males; ISS 22 +/- 13; 18.6% lethality). From more than 30 initially documented variables, the age, the GCS, the ISS, the base excess (BE) and the prothrombin time were the most important prognostic factors to predict the probability of death (P(death)). The following prognostic model was developed: P(death) = 1/1 + e(-[k + beta 1(age) + beta 2(GCS) + beta 3(ISS) + beta 4(BE) + beta 5(prothrombin time)]) where: k = -0.1551, beta 1 = 0.0438 with p < 0.0001, beta 2 = -0.2067 with p < 0.0001, beta 3 = 0.0252 with p = 0.0071, beta 4 = -0.0840 with p < 0.0001 and beta 5 = -0.0359 with p < 0.0001. Each of the five variables contributed significantly to the multifactorial model. CONCLUSIONS: These data show that the age, GCS, ISS, base excess and prothrombin time are potentially important predictors to initially identify multiple trauma patients with a high risk of lethality. With the base excess and prothrombin time value, as only variables of this multifactorial model that can be therapeutically influenced, it might be possible to better guide early and aggressive therapy.

[Severe craniocerebral trauma in multiple trauma. An assessment of the interaction of local and systemic mediator responses]. / Das schwere Schädel-Hirn-Trauma beim Mehrfachverletzten. Eine Bestandsaufnahme zur Interaktion lokaler und systemischer Mediatorwirkungen.

Isolated severe head trauma (SHT) or SHT in combination with multiple injuries are important factors for the prognosis of morbidity and mortality in patients suffering from the consequences of accidents. The prognosis mainly depends on the presence of primary mechanic brain injury and the development of secondary brain damage. Causes for the development of secondary brain damage are the intracranial space demand after traumatic injury and edema formation which may result in iscemia, as well as inflammatory processes. Both isolated SHT and polytrauma with or without brain damage may result in a systemic inflammatory response syndrome (SIRS) due to the synthesis of cytokines and other inflammatory mediators which may cause a single or multiple organ failure (MOF). Often the organism is able to survive isolated traumatic injuries and functional disturbances, but in combination or cumulation they may be lethal. The hypermetabolism after SHT is often regarded as an interaction between the central nervous system and the whole organism by the activation of the neuroendocrine axis. In contrast to the consequences of SHT for the whole organism, multiple injuries after polytrauma may affect brain functions, such as the shock dependent disturbance of the brain perfusion accompanied by brain hypoxia which may lead to an aggravated prognosis. Moreover, coagulation, metabolism and fracture healing are influenced by the onset of SIRS as well. Our knowledge about the bidirectional inflammatory interaction between brain and whole organism is still limited. In this context, the effects of secondary surgical interventions which may additionally, stress a traumatized body have to be considered and are the subject for actual clinical discussions and experimental studies. This article tries to summarize some important aspects on this topic.

[Systematic development of a scale for determination of health-related quality of life in multiple trauma patients. The Polytrauma Outcome (POLO) Chart]. / Systematische Entwicklung eines Messinstruments zur Erfassung der gesundheitsbezogenen Lebensqualität beim polytraumatisierten Patienten. Die Polytrauma-Outcome-(POLO-)Chart.

Even years after having sustained multiple injuries patients often suffer from its sequelae. These comprise restrictions in physical function, but also pain, social and psychological impairments. Although the Meran Consensus Conference in 1990 defined the contents of "quality of life" (QoL) measures in surgery, still no instrument is available for the valid assessment of all relevant QoL domains in multiple injured patients. This paper describes the systematic development of a modular instrument for the assessment of health related QoL. Within three phases (phase I: generation of items, phase II: item reduction, phase III: pre-testing in 70 multiple injured and control patients) a questionnaire of 57 items was developed, which measures all relevant trauma-related aspects of QoL after acute hospital care. In combination with the Glascow Outcome Scale (GOS), the EUROQOL and the SF-36, the newly developed instrument builds the Polytrauma Outcome Chart (POLO-Chart) which will also be used as "Part E" for outcome assessment within the "Trauma registry" of the German Society for Trauma Surgery. In phase IV, the POLO-Chart will finally be validated in five trauma centres (Celle, Essen, Hanover, Cologne und Munich).

A vaccine candidate from the sexual stage of human malaria that contains EGF-like domains.

Malaria vaccines are being developed against different stages in the parasite's life cycle, each increasing the opportunity to control malaria in its diverse settings. Sporozoite vaccines are designed to prevent mosquito-induced infection; first generation recombinant or synthetic peptide vaccines have been tested in humans. Asexual erythrocytic stage vaccines, developed to prevent or reduce the severity of disease, have been tested in animals and in humans. A third strategy is to produce sexual stage vaccines that would induce antibodies which would prevent infection of mosquitoes when ingested in a bloodmeal containing sexual stage parasites. Although not directly protective, the sexual stage vaccine combined with a sporozoite or asexual stage vaccine (protective component) could prolong the useful life of the protective component by reducing transmission of resistant vaccine-induced mutants. In areas of low endemnicity, the sexual stage vaccine could reduce transmission below the critical threshold required to maintain the infected population, thereby assisting in the control or eradication of malaria. Transmission of Plasmodium falciparum, the major human malaria, can be blocked by monoclonal antibodies against three sexual stage-specific antigens. We have cloned the gene encoding the surface protein of relative molecular mass Mr 25,000 (25K; Pfs25), expressed on zygotes and ookinetes of P. falciparum. The deduced amino-acid sequence consists of a signal sequence, a hydrophobic C-terminus, and four tandem epidermal growth factor EGF-like domains.

The gag gene products of human immunodeficiency virus type 1: alignment within the gag open reading frame, identification of posttranslational modifications, and evidence for alternative gag precursors.

Seven human immunodeficiency virus gag polypeptides were identified in the purified virus and in infected CD4+ lymphocytes by peptide mapping and limited amino acid sequencing of immune-purified proteins. Two gag polyproteins of 55,000 (p55) and 41,000 (p41) daltons were rapidly labeled and readily processed into the major internal gag proteins that were aligned within the gag open reading frame (ORF) as NH2-p16 (MA)-p24 (CA)-p9 (NC)-p7-COOH. The myristoylated p16 (matrix, MA) protein was processed from the myristoylated p55 gag precursor protein. The immunoreactivity of the p16 (MA) protein with region-specific gag antisera and the conservation of the N-terminal myristyl group of the p55 precursor protein in p16 (MA) confirmed its position as the N-terminal-most protein. The p9 (nucleocapsid, NC) protein was localized to residue 378 of the gag ORF, next to the C terminus of the p24/p25 (core antigen, CA) protein. The p9 protein had a repeating Cys residue containing motif which is found in the nucleic acid-binding Cys residue-containing proteins of retroviruses. The p24 (CA) protein, which was localized to residue 133 of the gag ORF, was apparently derived by C-terminal processing of an intermediate polypeptide, p25. Both the mature p24 (CA) and p16 (MA) proteins were phosphorylated at Ser residue(s). We also identified two forms of gag p41 species, one resulting from the C-terminal processing of p55 and the other originating either from N-terminal processing of p55 or from de novo synthesis.

Purification and structural characterization of the putative gag-pol protease of human immunodeficiency virus.

We have purified a 10,774-dalton protein from human immunodeficiency virus (HIV) type 1 that is encoded in the protease domain of the pol open reading frame (ORF). Radiochemical amino acid microsequencing identified 12 amino acids from the stretch of 39 N-terminal residues of this protein, beginning with a PQITLW sequence at position 69 of the pol ORF. Radiosequencing of selected tryptic peptides of the protein identified 11 additional residues (Leu-9 and Val-2) in six peptides encompassing the entire molecule of 99 residues. A protein of similar size and identical N-terminal sequence (determined through the first 39 residues) was present among the processed HIV pol gene products in Escherichia coli which expressed the entire HIV pol ORF. The C terminus of both the viral and E. coli-expressed proteins was inferred to be contiguous with the N terminus of the p64-p51 reverse transcriptase on the basis of tryptic mapping and specific immunoreactivity with an antiserum against a dodecapeptide located upstream of the reverse transcriptase. Thus, the initial processing of the pol precursor that generates the native protease is apparently preserved across phylogenetic barriers. Although the purified viral protease lacked measurable proteolytic activity, the bacterial extracts were capable of processing an HIV gag precursor protein synthesized in E. coli.