The effect of anti-integrin monoclonal antibodies on antigen-induced pulmonary inflammation in allergic rabbits

https://doi.org/10.1016/S1094-5539(03)00069-5Get rights and content

Abstract

The integrin adhesion molecules are involved in the recruitment and activation of inflammatory cells at sites of inflammation in a variety of diseases. In the present study, we have investigated the effects of blocking monoclonal antibodies (mAbs) directed against CD49d (α4 integrin), CD182 integrin) and the α sub-units of β2 integrin CD11a (LFA-1 integrin) and CD11b (Mac-1 integrin), on antigen (Ag)-induced acute bronchoconstriction and cellular recruitment in allergic rabbits in vivo. Inhaled Ag (Alternaria tenuis) challenge of neonatally sensitised rabbits caused an acute bronchoconstriction demonstrated by an increase in lung resistance (RL) and decrease in dynamic compliance (Cdyn) and pulmonary inflammation characterised by an increase in bronchoalveolar lavage (BAL) inflammatory cells, particularly eosinophils, 24 h after challenge.

Pre-treatment with the anti-CD49d mAb (Max-68P), significantly inhibited the Ag-induced acute bronchoconstriction in terms of RL and (Cdyn). Treatment with the other anti-integrin mAbs had no effect on the acute bronchoconstriction after inhaled Ag challenge.

Pre-treatment with the anti-integrin mAbs had differential effects in blocking the recruitment of inflammatory cells 24 h after inhaled Ag in the allergic rabbits. The data show that in the allergic rabbit model of asthma, VLA-4 (CD49d/CD29) only, is involved in the acute bronchoconstriction, suggesting an involvement of mast cell degranulation. Furthermore, eosinophil recruitment and activation appears to be mediated by a combination of VLA-4 (CD49d/CD29) and LFA-1 (CD18/CD11a). However in contrast, lymphocyte recruitment appears to be mediated by a combination of LFA-1 (CD18/CD11a) and Mac-1 (CD18/CD11b).

Introduction

The integrin adhesion molecules are implicated in the migration and activation of inflammatory cells to inflamed lung tissue which is considered central to the pathophysiology of asthma [1], [2].

The principle cell types recruited into the asthmatic lung are the eosinophils and lymphocytes and there is also an increase in the number of mast cells present in the lung. These cells express a variety of integrins, which bind to ligands present on vascular endothelial cells and the tissue matrix, to mediate extravasation and cell migration to inflamed tissues [2].

Two principal integrin families are the α4 and the β2 integrins. The α4 integrin CD49d/CD29 (VLA-4; α4β1) binds endothelial VCAM-1 and tissue matrix fibronectin. Another important α4 integrin is α4β7 which may be involved in binding of eosinophils and lymphocytes to MadCAM-1 in gut associated tissues [3], [4]. The β2 integrin (CD18) forms heterodimers with three distinct α-chain polypeptides, CD11a (LFA-1), CD11b (Mac-1) and CD11c (p150/95). These integrins bind to ICAMs present on vascular endothelial cells.

The adhesion molecule VLA-4 is thought to be important in asthma since it is expressed on eosinophils and T-lymphocytes [2] and more recently on mast cells [5]. Furthermore, expression of the VCAM-1 is increased in tissues from subjects with asthma [6]. Blocking anti-α4 (CD49d) monoclonal antibodies (mAb) have previously been shown to suppress antigen (Ag)-induced pulmonary inflammation in a variety of species including mice [7], [8], rat [9] and guinea-pig [10], [11]. The β2 integrins are also widely expressed on inflammatory cells in asthma and increased expression of ICAM-1 has been shown in asthmatic tissue [12]. Additionally, blocking anti-CD18 (β2) mAbs have also been shown to reduce Ag-induced pulmonary inflammation in guinea-pigs [13] and rabbits [14].

We have also previously reported that the Ag-induced acute bronchoconstriction and eosinophilia is dependent on CD49d (α4) in allergic rabbits [15]. Moreover, we have demonstrated that the eosinophil recruitment parallels the increased expression of VCAM-1 in rabbit lungs following Ag challenge [16]. To further characterise the adhesion molecules involved in the mast cell mediated acute bronchoconstriction and the inflammatory cell recruitment in the allergic rabbit model, we have investigated the effects of blocking mAbs directed against CD49d (α4), CD18 (β2) and α sub-units of CD18, CD11a (LFA-1) and CD11b (Mac-1) on Ag-induced acute airways obstruction and pulmonary inflammation.

Section snippets

Animals

New Zealand white rabbits (NZW) of either sex (Harlan UK, Ltd) weighing 2.4–3.5 kg at three months of age were used throughout the study. All animals received food and water ad libitum and were housed for at least one week prior to experimentation. The neonatal immunisation of rabbits has been described in detail elsewhere [17]. Briefly, rabbits were injected intraperitoneally (0.5 ml) within 24 h of birth with Alternaria tenuis (Ag) extract (40,000 PNU ml−1) in aluminium hydroxide (Al(OH)3)

Acute bronchoconstriction

Treatment with either the control or anti-integrin mAbs had no effect on baseline lung function values prior to Ag inhalation (RL; 35 ±5 cm H2O l−1 s−1 and Cdyn; 4.0±0.2 ml cm H2O−1).

In control mAb (101.4) treated rabbits, saline challenge caused a small increase (12–15%) in resistance (RL) and fall in dynamic compliance (Cdyn). In contrast, inhaled Ag (A. tenuis) caused a significant 45% increase in baseline RL and a 40% fall in Cdyn in control mAb (101.4) treated rabbits (Fig. 1A and B). The

Discussion

Asthma is a chronic inflammatory condition characterised by the accumulation of pulmonary eosinophils and lymphocytes [26], along with intermittent variable changes in airways obstruction. In allergic asthma, mast cell activation is thought to play a role in the airway obstruction. The integrin adhesion molecules are involved in the trafficking of inflammatory cells from the circulation into the inflamed lung [1], [2] and has also recently been implicated in the acute mast cell degranulation

References (38)

  • H. Nakajima et al.

    Role of vascular cell adhesion molecule 1 (VCAM-1) very late activation antigen 4 (VLA-4) and intracellular adhesion molecule 1 (VCAM-1) lymphocyte function-associated antigen 1 (LFA-1) interactions in antigen-induced eosinophil and T cell recruitment into the tissue

    J Exp Med

    (1994)
  • W.R. Henderson et al.

    Blockade of CD49d (α4 integrin) on intrapulmonary but not circulating leukocytes inhibits airway inflammation and hyperresponsiveness in a mouse model of asthma

    J Clin Invest

    (1997)
  • I.M. Richards et al.

    Role of very late activation antigen-4 in the antigen-induced accumulation of eosinophils and lymphocytes in the lungs and airway lumen of sensitised brown Norway rats

    Am J Respir Cell Mol Biol

    (1996)
  • M. Pretolani et al.

    Antibody to very late antigen 4 prevents antigen-induced bronchial hyperreactivity and cellular infiltration in the guinea-pig airways

    J Exp Med

    (1994)
  • Y. Ohkawara et al.

    In situ expression of the cell adhesion molecules in bronchial tissues from asthmatics with air flow limitation: in vivo evidence of VCAM-1/VLA4 interaction in selective eosinophil infiltration

    Am J Respir Cell Mol Biol

    (1995)
  • T.C. Noonan et al.

    The effects of an anti-CD18 antibody (R15.7) in antigen-induced airway hyperresponsiveness (AH) and cell influx in guinea-pigs

    Agents Actions

    (1991)
  • A.Z. El-Hashim et al.

    The effect of R 15.7/HO, an anti-CD 18 antibody, on the late airway response and airway hyperresponsiveness in an allergic rabbit model

    Br J Pharmacol

    (1997)
  • M.H. Gascoigne et al.

    Anti-VLA4 monoclonal antibody (Max68-P) inhibits antigen-induced airway responses in the neonatally sensitised rabbit

    Am J Respir Crit Care Med

    (1999)
  • P.M. Hughes et al.

    Time course of cellular recruitment and expression of VCAM-1 following inhaled antigen challenge in the neonatally immunised rabbit

    Br J Pharmacol

    (1999)
  • Cited by (32)

    • Mucosal Eosinophils

      2015, Mucosal Immunology: Fourth Edition
    • Validating 123I-metaiodobenzylguanidine as a platelet marker for non-invasive imaging in rabbits

      2011, Journal of Pharmacological and Toxicological Methods
      Citation Excerpt :

      However the platelet size of human (2–4 µm diameter) and rabbit (2.02 to 3.4 µm diameter) are in a similar range. Following antigen challenge allergic rabbits show similar pathological features to human asthma including acute bronchoconstriction, late phase airway obstruction, airway hyperresponsiveness and eosinophilia (Gascoigne et al., 2003) and the rabbit model of allergic inflammation has been used in research evaluating the mechanisms of asthma. 123I-MIBG uptake by rabbit platelets in vitro reached a maximum in the first 8 h (55.8 ± 16.4%).

    • The rabbit as a model to study asthma and other lung diseases

      2008, Pulmonary Pharmacology and Therapeutics
      Citation Excerpt :

      Furthermore, the expression of VCAM-1 is increased in airway tissue obtained from subjects with asthma [47]. In the allergic rabbit model, anti-α4 monoclonal antibodies suppress acute bronchoconstriction induced by antigen and the effects appear likely to be due to the inhibition of α4β1[48]. The β2-integrins (CD-18) are widely expressed on inflammatory cells and form heterodimers that bind to ICAMs located on vascular endothelial cells.

    View all citing articles on Scopus
    View full text