Targeting of multiple tumor-associated antigens by individual T cell receptors during successful cancer immunotherapy

The T cells of the immune system can target tumors and clear solid cancers following tumor-infiltrating lymphocyte (TIL) therapy. We used combinatorial peptide libraries and a proteomic database to reveal the antigen specificities of persistent cancer-specific T cell receptors (TCRs) following successful TIL therapy for stage IV malignant melanoma. Remarkably, individual TCRs could target multiple different tumor types via the HLA A∗02:01-restricted epitopes EAAGIGILTV, LLLGIGILVL, and NLSALGIFST from Melan A, BST2, and IMP2, respectively. Atomic structures of a TCR bound to all three antigens revealed the importance of the shared x-x-x-A/G-I/L-G-I-x-x-x recognition motif. Multi-epitope targeting allows individual T cells to attack cancer in several ways simultaneously. Such "multipronged" T cells exhibited superior recognition of cancer cells compared with conventional T cell recognition of individual epitopes, making them attractive candidates for the development of future immunotherapies.

Emergence of immune escape at dominant SARS-CoV-2 killer T cell epitope

We studied the prevalent cytotoxic CD8 T cell response mounted against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike glycoprotein269-277 epitope (sequence YLQPRTFLL) via the most frequent human leukocyte antigen (HLA) class I worldwide, HLA A∗02. The Spike P272L mutation that has arisen in at least 112 different SARS-CoV-2 lineages to date, including in lineages classified as "variants of concern," was not recognized by the large CD8 T cell response seen across cohorts of HLA A∗02+ convalescent patients and individuals vaccinated against SARS-CoV-2, despite these responses comprising of over 175 different individual T cell receptors. Viral escape at prevalent T cell epitopes restricted by high frequency HLAs may be particularly problematic when vaccine immunity is focused on a single protein such as SARS-CoV-2 Spike, providing a strong argument for inclusion of multiple viral proteins in next generation vaccines and highlighting the need for monitoring T cell escape in new SARS-CoV-2 variants.

A collection of cytochrome P450 monooxygenase genes involved in modification and detoxification of herbicide atrazine in rice (Oryza sativa) plants

Plant cytochrome P450 monooxygenases constitute one of the largest families of protein genes involved in plant growth, development and acclimation to biotic and abiotic stresses. However, whether these genes respond to organic toxic compounds and their biological functions for detoxifying toxic compounds such as herbicides in rice are poorly understood. The present study identified 201 genes encoding cytochrome P450s from an atrazine-exposed rice transcriptome through high-throughput sequencing. Of these, 69 cytochrome P450 genes were validated by microarray and some of them were confirmed by real time PCR. Activities of NADPH-cytochrome P450 reductase (CPR) and p-nitroanisole O-demethylase (PNOD) related to toxicity were determined and significantly induced by atrazine exposure. To dissect the mechanism underlying atrazine modification and detoxification by P450, metabolites (or derivatives) of atrazine in plants were analyzed by ultra performance liquid chromatography mass spectrometry (UPLC/MS). Major metabolites comprised desmethylatrazine (DMA), desethylatrazine (DEA), desisopropylatrazine (DIA), hydroxyatrazine (HA), hydroxyethylatrazine (HEA) and hydroxyisopropylatrazine (HIA). All of them were chemically modified by P450s. Furthermore, two specific inhibitors of piperonyl butoxide (PBO) and malathion (MAL) were used to assess the correlation between the P450s activity and rice responses including accumulation of atrazine in tissues, shoot and root growth and detoxification.

Accumulation and toxicological response of atrazine in rice crops

Atrazine is one of the most widely used herbicides for controlling weeds and grasses. Due to its intensive use, it has become a serious contaminant in soil and water. To evaluate impact of atrazine on graminaceous crops, experiments focusing on atrazine accumulation and toxic response in rice (Oryza sativa) were carried out. Treatment with atrazine at 0.05-0.8 mg L(-1) for 6 d reduced elongation of shoot and root. Compared with a mock treatment, the elongation of shoot with atrazine was 67.1 percent of the control, whereas that of root was 79.5 percent, indicating that the shoot was more affected than the root. Atrazine was readily absorbed by rice from media. Although the quantitative absorption of atrazine was positively correlated with the external supply of the herbicide, translocation of atrazine from roots to the above-ground was reduced from 39.88±6.26 (at 0.05 mg L(-1)) to 9.25±0.27 (0.8 mg L(-1)). While accumulation of atrazine in rice plants led to toxic responses such as over-generation of hydrogen peroxide and superoxide anions, it triggered the plant defense system against the herbicide-induced oxidative stress. This was best presented by the enhanced activities of several antioxidant enzymes (e.g. superoxide dismutase, catalase and peroxidase) and expression of genes responsible for the tolerance to atrazine toxicity.

Sentinel lymphadenectomy for breast cancer in a community managed care setting

PURPOSE

To evaluate the feasibility, accuracy, and reproducibility of intraoperative lymphatic mapping and sentinel lymphadenectomy (IOLM/SL) in the staging of breast cancer patients in a community managed care setting.

PATIENTS AND METHODS

One hundred forty-five patients with primary breast cancer were prospectively studied over a 26-month period. They underwent vital dye injection at their primary breast cancer site. Lymphatic channels were traced to the sentinel lymph node, which was excised, serially sectioned, and examined. A level I and II axillary lymph node dissection and definitive breast surgery were then performed.

RESULTS

Sentinel nodes were identified in 103 of 145 procedures (71.0%). Sentinel and nonsentinel lymph nodes were concordant in 100 of 103 cases (97.1%). Three patients (9.7%) had falsely negative sentinel nodes; there were none in the last 80 patients. Of 28 positive sentinel nodes, 12 (42.9%) represented the only tumor-containing node within the axilla. Sentinel nodes were significantly more likely to contain tumor than nonsentinel nodes (33/50, 66.0% vs 54/467, 11.6%, P < 0.0001). IOLM/SL identified more micrometastases (< 2 mm) than standard axillary lymph node dissection (13/33, 39.6% vs 4/177, 2.2%, P < 0.001). Nine of 42 patients (21.4%) whose sentinel node could not be identified had five or more nodal metastases. Two of six patients with presumed Tis primaries had nodal metastases.

DISCUSSION

IOLM/SL accurately identifies the sentinel lymph node(s) most likely to contain metastatic disease. A procedural learning curve was present. An unsuccessful IOLM/SL was a risk factor for considerable nodal metastases. IOLM/SL with a tumor-free sentinel node may obviate a formal axillary lymph node dissection. The technique was feasible, economical, and reproducible within the context of a community managed care facility, while not placing exacting demands on operating room, pathology, or nuclear medicine personnel.

Outpatient definitive breast cancer surgery

We attempted to show that surgical treatment of breast cancer, including axillary lymph node dissection with or without concomitant partial mastectomy (ALND), simple mastectomy (SM), and modified radical mastectomy (MRM) can be performed safely in an outpatient setting. The records of 100 consecutive women undergoing definitive breast cancer surgery by the authors between August 1994 and July 1996 were retrospectively reviewed. Average age was 54 +/- 10 years. Fifty patients were discharged the day of surgery, 44 were hospitalized, and 6 remained 2 or more days postoperatively. Outpatients were more likely to have undergone ALND or SM (42 versus 23 procedures) and more often completed surgery in the morning (36 versus 12); P < 0.05. Eight patients of 35 with MRM were discharged the same day. One patient was readmitted with a wound infection. There were no major complications or deaths. Ninety-four per cent of patients were discharged within 23 hours of surgery; half were discharged the same day. No complications occurred in outpatients, and there were no readmissions. For patients admitted overnight, no complications were detected during the overnight hospital stay. In conclusion, breast cancer surgery, from ALND to SM or MRM, can be safely and comfortably performed on an outpatient basis.

Segmental mastectomy and tamoxifen alone provide adequate locoregional control of breast cancer in elderly women

We wished to determine whether tamoxifen and local excision without breast radiation or axillary lymph node dissection provides adequate local and regional control of breast cancer in elderly women. The records of 36 women with breast cancer who were more than 70 years old and were treated only with tamoxifen and local excision from January 1985 to July 1996 were retrospectively reviewed. These patients had refused, or were considered too ill for, standard therapy. The mean follow-up was 44.1 months. Twenty-two (61%) were alive without disease, and six (17%) died of unrelated causes, without recurrence. Two (6%) were alive with metastasis, and five (14%) died with metastasis. One patient developed a breast recurrence, which was reexcised. A second patient developed metastasis and axillary recurrence, which was treated with modified radical mastectomy. Pathologic grade, tumor size, and estrogen receptor and margin status were not predictive of recurrence. In conclusion, despite the omission of breast radiation and axillary dissection, there were only two locoregional recurrences, and both were easily treated surgically. In this select group of patients, local excision and tamoxifen provided adequate locoregional control of breast cancer in elderly women.

Superoxide dismutase and allopurinol improve survival in an animal model of hemorrhagic shock

We studied the efficacy of resuscitation with antioxidants in an animal model of hemorrhagic shock. Male Sprague-Dawley rats were anesthetized, and 27 mL/kg of blood was withdrawn from the carotid artery over 2 minutes. The animals remained in hemorrhagic shock for 45 minutes, followed by 1 hour of resuscitation. Experimental groups were as follows: 1) 15,000 u/kg superoxide dismutase (SOD) in 54 mL/kg lactated Ringer (LR); 2) 175,000 u/kg catalase (CAT) in LR; 3) 15,000 u/kg SOD+175,000 u/kg CAT in LR; 4) allopurinol in LR; 5) deferoxamine bound to pentafraction (DFO), 27 mL/kg; 6) pentafraction alone; and 7) LR alone. Compared with resuscitation with LR alone, SOD and allopurinol improved survival over 72 hours, P < 0.05. Survival with SOD+CAT was not different from LR alone. Deferoxamine bound to pentafraction did not increase survival over that with pentafraction alone. CAT had increased mortality compared to LR, P < 0.01. The efficacy of both SOD and allopurinol in decreasing mortality suggests the importance of superoxide radicals after hemorrhagic shock and resuscitation. These and other antioxidants are potential therapeutic agents in the clinical setting of trauma and hemorrhagic shock.

Trauma causes early release of soluble receptors for tumor necrosis factor

The importance of tumor necrosis factor (TNF) in the pathophysiology of trauma and hemorrhagic shock is not known. In addition, TNF bioactivity may be modulated by soluble forms of the 55-kd and 75-kd membrane receptors (TNFR). This study was undertaken to determine circulating levels of TNF and TNFR after trauma. Nine severely injured male patients were studied. The mean age was 30 +/- 10 years (range, 15-45). The mean Injury Severity Score (ISS) was 31.3 +/- 17.6 (range, 10-59), and the mean Revised Trauma Score (RTS), 5.7 +/- 2.2 (range, 0.7-7.8). Serum was obtained immediately upon arrival at our trauma center, within 1 hour of injury. The TNF and TNFR levels in the serum were measured using ELISA techniques. After trauma, 55-kd and 75-kd TNFR levels were significantly elevated above those of controls (6.99 +/- 4.57 ng/mL and 5.42 +/- 1.88 ng/mL, respectively, p < 0.01); TNF levels were not increased. Patient serum containing TNFR inhibited in vitro TNF cytotoxicity and correlated with 55-kd TNFR levels (p < 0.05). We conclude that TNF is a strong releasing factor for TNFR; the presence of TNFR may be indirect evidence that TNF is present after trauma, despite low measured levels. Both TNF and TNFR may be more important in trauma and hemorrhagic shock than previously thought.